diff --git a/configure.ac b/configure.ac
index ad8fd06..cdb0f83 100644
--- a/configure.ac
+++ b/configure.ac
@@ -158,9 +158,14 @@ AC_CHECK_HEADERS([sys/param.h])
 # Checks for global variable declarations.
 AC_CHECK_DECLS([optreset])
 
+# Checks for structures.
+AC_CHECK_MEMBERS([struct tm.tm_gmtoff],,,[
+#include <time.h>
+])
+
 # Checks for library functions.
 AC_FUNC_STRERROR_R
-AC_CHECK_FUNCS([localtime_r gmtime_r])
+AC_CHECK_FUNCS([localtime_r gmtime_r timegm _mkgmtime])
 AC_CHECK_FUNCS([getopt_long])
 
 # Versioning.
diff --git a/examples/Makefile.am b/examples/Makefile.am
index e830769..6b70f99 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -17,6 +17,7 @@ dctool_SOURCES = \
 	dctool_parse.c \
 	dctool_read.c \
 	dctool_write.c \
+	dctool_timesync.c \
 	dctool_fwupdate.c \
 	output.h \
 	output-private.h \
diff --git a/examples/dctool.c b/examples/dctool.c
index df7fe01..f62b13c 100644
--- a/examples/dctool.c
+++ b/examples/dctool.c
@@ -63,6 +63,7 @@ static const dctool_command_t *g_commands[] = {
 	&dctool_parse,
 	&dctool_read,
 	&dctool_write,
+	&dctool_timesync,
 	&dctool_fwupdate,
 	NULL
 };
diff --git a/examples/dctool.h b/examples/dctool.h
index cc6a393..06e58a8 100644
--- a/examples/dctool.h
+++ b/examples/dctool.h
@@ -50,6 +50,7 @@ extern const dctool_command_t dctool_dump;
 extern const dctool_command_t dctool_parse;
 extern const dctool_command_t dctool_read;
 extern const dctool_command_t dctool_write;
+extern const dctool_command_t dctool_timesync;
 extern const dctool_command_t dctool_fwupdate;
 
 const dctool_command_t *
diff --git a/examples/dctool_timesync.c b/examples/dctool_timesync.c
new file mode 100644
index 0000000..3a59af5
--- /dev/null
+++ b/examples/dctool_timesync.c
@@ -0,0 +1,162 @@
+/*
+ * libdivecomputer
+ *
+ * Copyright (C) 2017 Jef Driesen
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#ifdef HAVE_GETOPT_H
+#include <getopt.h>
+#endif
+
+#include <libdivecomputer/context.h>
+#include <libdivecomputer/descriptor.h>
+#include <libdivecomputer/device.h>
+
+#include "dctool.h"
+#include "common.h"
+#include "utils.h"
+
+static dc_status_t
+do_timesync (dc_context_t *context, dc_descriptor_t *descriptor, const char *devname, const dc_datetime_t *datetime)
+{
+	dc_status_t rc = DC_STATUS_SUCCESS;
+	dc_device_t *device = NULL;
+
+	// Open the device.
+	message ("Opening the device (%s %s, %s).\n",
+		dc_descriptor_get_vendor (descriptor),
+		dc_descriptor_get_product (descriptor),
+		devname ? devname : "null");
+	rc = dc_device_open (&device, context, descriptor, devname);
+	if (rc != DC_STATUS_SUCCESS) {
+		ERROR ("Error opening the device.");
+		goto cleanup;
+	}
+
+	// Register the event handler.
+	message ("Registering the event handler.\n");
+	int events = DC_EVENT_WAITING | DC_EVENT_PROGRESS | DC_EVENT_DEVINFO | DC_EVENT_CLOCK | DC_EVENT_VENDOR;
+	rc = dc_device_set_events (device, events, dctool_event_cb, NULL);
+	if (rc != DC_STATUS_SUCCESS) {
+		ERROR ("Error registering the event handler.");
+		goto cleanup;
+	}
+
+	// Register the cancellation handler.
+	message ("Registering the cancellation handler.\n");
+	rc = dc_device_set_cancel (device, dctool_cancel_cb, NULL);
+	if (rc != DC_STATUS_SUCCESS) {
+		ERROR ("Error registering the cancellation handler.");
+		goto cleanup;
+	}
+
+	// Syncronize the device clock.
+	message ("Syncronize the device clock.\n");
+	rc = dc_device_timesync (device, datetime);
+	if (rc != DC_STATUS_SUCCESS) {
+		ERROR ("Error syncronizing the device clock.");
+		goto cleanup;
+	}
+
+cleanup:
+	dc_device_close (device);
+	return rc;
+}
+
+static int
+dctool_timesync_run (int argc, char *argv[], dc_context_t *context, dc_descriptor_t *descriptor)
+{
+	int exitcode = EXIT_SUCCESS;
+	dc_status_t status = DC_STATUS_SUCCESS;
+
+	// Default option values.
+	unsigned int help = 0;
+
+	// Parse the command-line options.
+	int opt = 0;
+	const char *optstring = "h";
+#ifdef HAVE_GETOPT_LONG
+	struct option options[] = {
+		{"help",        no_argument,       0, 'h'},
+		{0,             0,                 0,  0 }
+	};
+	while ((opt = getopt_long (argc, argv, optstring, options, NULL)) != -1) {
+#else
+	while ((opt = getopt (argc, argv, optstring)) != -1) {
+#endif
+		switch (opt) {
+		case 'h':
+			help = 1;
+			break;
+		default:
+			return EXIT_FAILURE;
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	// Show help message.
+	if (help) {
+		dctool_command_showhelp (&dctool_timesync);
+		return EXIT_SUCCESS;
+	}
+
+	// Get the system time.
+	dc_datetime_t datetime = {0};
+	dc_ticks_t now = dc_datetime_now ();
+	if (!dc_datetime_localtime(&datetime, now)) {
+		message ("ERROR: Failed to get the system time.\n");
+		exitcode = EXIT_FAILURE;
+		goto cleanup;
+	}
+
+	// Synchronize the device clock.
+	status = do_timesync (context, descriptor, argv[0], &datetime);
+	if (status != DC_STATUS_SUCCESS) {
+		message ("ERROR: %s\n", dctool_errmsg (status));
+		exitcode = EXIT_FAILURE;
+		goto cleanup;
+	}
+
+cleanup:
+	return exitcode;
+}
+
+const dctool_command_t dctool_timesync = {
+	dctool_timesync_run,
+	DCTOOL_CONFIG_DESCRIPTOR,
+	"timesync",
+	"Synchronize the device clock",
+	"Usage:\n"
+	"   dctool timesync [options]\n"
+	"\n"
+	"Options:\n"
+#ifdef HAVE_GETOPT_LONG
+	"   -h, --help   Show help message\n"
+#else
+	"   -h   Show help message\n"
+#endif
+};
diff --git a/examples/output_xml.c b/examples/output_xml.c
index 45c95c2..237f929 100644
--- a/examples/output_xml.c
+++ b/examples/output_xml.c
@@ -230,9 +230,16 @@ dctool_xml_output_write (dctool_output_t *abstract, dc_parser_t *parser, const u
 		goto cleanup;
 	}
 
-	fprintf (output->ostream, "<datetime>%04i-%02i-%02i %02i:%02i:%02i</datetime>\n",
-		dt.year, dt.month, dt.day,
-		dt.hour, dt.minute, dt.second);
+	if (dt.timezone == DC_TIMEZONE_NONE) {
+		fprintf (output->ostream, "<datetime>%04i-%02i-%02i %02i:%02i:%02i</datetime>\n",
+			dt.year, dt.month, dt.day,
+			dt.hour, dt.minute, dt.second);
+	} else {
+		fprintf (output->ostream, "<datetime>%04i-%02i-%02i %02i:%02i:%02i %+03i:%02i</datetime>\n",
+			dt.year, dt.month, dt.day,
+			dt.hour, dt.minute, dt.second,
+			dt.timezone / 3600, (dt.timezone % 3600) / 60);
+	}
 
 	// Parse the divetime.
 	message ("Parsing the divetime.\n");
diff --git a/include/libdivecomputer/datetime.h b/include/libdivecomputer/datetime.h
index d8f596b..768883d 100644
--- a/include/libdivecomputer/datetime.h
+++ b/include/libdivecomputer/datetime.h
@@ -26,6 +26,8 @@
 extern "C" {
 #endif /* __cplusplus */
 
+#define DC_TIMEZONE_NONE 0x80000000
+
 #if defined (_WIN32) && !defined (__GNUC__)
 typedef __int64 dc_ticks_t;
 #else
@@ -39,6 +41,7 @@ typedef struct dc_datetime_t {
 	int hour;
 	int minute;
 	int second;
+	int timezone;
 } dc_datetime_t;
 
 dc_ticks_t
diff --git a/include/libdivecomputer/device.h b/include/libdivecomputer/device.h
index 7ba4bd6..f6d415c 100644
--- a/include/libdivecomputer/device.h
+++ b/include/libdivecomputer/device.h
@@ -84,9 +84,6 @@ dc_device_set_events (dc_device_t *device, unsigned int events, dc_event_callbac
 dc_status_t
 dc_device_set_fingerprint (dc_device_t *device, const unsigned char data[], unsigned int size);
 
-dc_status_t
-dc_device_version (dc_device_t *device, unsigned char data[], unsigned int size);
-
 dc_status_t
 dc_device_read (dc_device_t *device, unsigned int address, unsigned char data[], unsigned int size);
 
@@ -99,6 +96,9 @@ dc_device_dump (dc_device_t *device, dc_buffer_t *buffer);
 dc_status_t
 dc_device_foreach (dc_device_t *device, dc_dive_callback_t callback, void *userdata);
 
+dc_status_t
+dc_device_timesync (dc_device_t *device, const dc_datetime_t *datetime);
+
 dc_status_t
 dc_device_close (dc_device_t *device);
 
diff --git a/include/libdivecomputer/hw_frog.h b/include/libdivecomputer/hw_frog.h
index 67f624f..0af10ca 100644
--- a/include/libdivecomputer/hw_frog.h
+++ b/include/libdivecomputer/hw_frog.h
@@ -36,9 +36,6 @@ extern "C" {
 dc_status_t
 hw_frog_device_version (dc_device_t *device, unsigned char data[], unsigned int size);
 
-dc_status_t
-hw_frog_device_clock (dc_device_t *device, const dc_datetime_t *datetime);
-
 dc_status_t
 hw_frog_device_display (dc_device_t *device, const char *text);
 
diff --git a/include/libdivecomputer/hw_ostc.h b/include/libdivecomputer/hw_ostc.h
index b68e083..b7daca7 100644
--- a/include/libdivecomputer/hw_ostc.h
+++ b/include/libdivecomputer/hw_ostc.h
@@ -43,9 +43,6 @@ typedef enum hw_ostc_format_t {
 dc_status_t
 hw_ostc_device_md2hash (dc_device_t *device, unsigned char data[], unsigned int size);
 
-dc_status_t
-hw_ostc_device_clock (dc_device_t *device, const dc_datetime_t *datetime);
-
 dc_status_t
 hw_ostc_device_eeprom_read (dc_device_t *device, unsigned int bank, unsigned char data[], unsigned int size);
 
diff --git a/include/libdivecomputer/hw_ostc3.h b/include/libdivecomputer/hw_ostc3.h
index bd0d2ed..c69dd93 100644
--- a/include/libdivecomputer/hw_ostc3.h
+++ b/include/libdivecomputer/hw_ostc3.h
@@ -39,9 +39,6 @@ hw_ostc3_device_version (dc_device_t *device, unsigned char data[], unsigned int
 dc_status_t
 hw_ostc3_device_hardware (dc_device_t *device, unsigned char data[], unsigned int size);
 
-dc_status_t
-hw_ostc3_device_clock (dc_device_t *device, const dc_datetime_t *datetime);
-
 dc_status_t
 hw_ostc3_device_display (dc_device_t *device, const char *text);
 
diff --git a/src/atomics_cobalt.c b/src/atomics_cobalt.c
index 91a6da6..7c7dccb 100644
--- a/src/atomics_cobalt.c
+++ b/src/atomics_cobalt.c
@@ -75,6 +75,7 @@ static const dc_device_vtable_t atomics_cobalt_device_vtable = {
 	NULL, /* write */
 	NULL, /* dump */
 	atomics_cobalt_device_foreach, /* foreach */
+	NULL, /* timesync */
 	atomics_cobalt_device_close /* close */
 };
 
diff --git a/src/atomics_cobalt_parser.c b/src/atomics_cobalt_parser.c
index 76b9531..a55e672 100644
--- a/src/atomics_cobalt_parser.c
+++ b/src/atomics_cobalt_parser.c
@@ -128,6 +128,7 @@ atomics_cobalt_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *dateti
 		datetime->hour   = p[0x18];
 		datetime->minute = p[0x19];
 		datetime->second = 0;
+		datetime->timezone = DC_TIMEZONE_NONE;
 	}
 
 	return DC_STATUS_SUCCESS;
diff --git a/src/citizen_aqualand.c b/src/citizen_aqualand.c
index 5e111da..47ba87f 100644
--- a/src/citizen_aqualand.c
+++ b/src/citizen_aqualand.c
@@ -51,6 +51,7 @@ static const dc_device_vtable_t citizen_aqualand_device_vtable = {
 	NULL, /* write */
 	citizen_aqualand_device_dump, /* dump */
 	citizen_aqualand_device_foreach, /* foreach */
+	NULL, /* timesync */
 	citizen_aqualand_device_close /* close */
 };
 
diff --git a/src/citizen_aqualand_parser.c b/src/citizen_aqualand_parser.c
index f89eacf..319dcf7 100644
--- a/src/citizen_aqualand_parser.c
+++ b/src/citizen_aqualand_parser.c
@@ -95,6 +95,7 @@ citizen_aqualand_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *date
 		datetime->hour   = bcd2dec(p[0x0A]);
 		datetime->minute = bcd2dec(p[0x0B]);
 		datetime->second = bcd2dec(p[0x0C]);
+		datetime->timezone = DC_TIMEZONE_NONE;
 	}
 
 	return DC_STATUS_SUCCESS;
diff --git a/src/cochran_commander.c b/src/cochran_commander.c
index 1ad38f0..b515909 100644
--- a/src/cochran_commander.c
+++ b/src/cochran_commander.c
@@ -29,16 +29,18 @@
 #include "serial.h"
 #include "array.h"
 #include "ringbuffer.h"
+#include "rbstream.h"
 
 #define C_ARRAY_SIZE(array) (sizeof (array) / sizeof *(array))
 
 #define MAXRETRIES 2
 
-#define COCHRAN_MODEL_COMMANDER_PRE21000 0
-#define COCHRAN_MODEL_COMMANDER_AIR_NITROX 1
-#define COCHRAN_MODEL_EMC_14 2
-#define COCHRAN_MODEL_EMC_16 3
-#define COCHRAN_MODEL_EMC_20 4
+#define COCHRAN_MODEL_COMMANDER_TM 0
+#define COCHRAN_MODEL_COMMANDER_PRE21000 1
+#define COCHRAN_MODEL_COMMANDER_AIR_NITROX 2
+#define COCHRAN_MODEL_EMC_14 3
+#define COCHRAN_MODEL_EMC_16 4
+#define COCHRAN_MODEL_EMC_20 5
 
 typedef enum cochran_endian_t {
 	ENDIAN_LE,
@@ -60,9 +62,6 @@ typedef struct cochran_data_t {
 	int invalid_profile_dive_num;
 
 	unsigned int logbook_size;
-
-	unsigned int sample_data_offset;
-	unsigned int sample_size;
 } cochran_data_t;
 
 typedef struct cochran_device_layout_t {
@@ -70,6 +69,7 @@ typedef struct cochran_device_layout_t {
 	unsigned int address_bits;
 	cochran_endian_t endian;
 	unsigned int baudrate;
+	unsigned int rbstream_size;
 	// Config data.
 	unsigned int cf_dive_count;
 	unsigned int cf_last_log;
@@ -89,6 +89,7 @@ typedef struct cochran_device_layout_t {
 	unsigned int pt_profile_pre;
 	unsigned int pt_profile_begin;
 	unsigned int pt_profile_end;
+	unsigned int pt_dive_number;
 } cochran_device_layout_t;
 
 typedef struct cochran_commander_device_t {
@@ -113,15 +114,42 @@ static const dc_device_vtable_t cochran_commander_device_vtable = {
 	NULL, /* write */
 	cochran_commander_device_dump, /* dump */
 	cochran_commander_device_foreach, /* foreach */
+	NULL, /* timesync */
 	cochran_commander_device_close /* close */
 };
 
+// Cochran Commander TM, pre-dates pre-21000 s/n
+static const cochran_device_layout_t cochran_cmdr_tm_device_layout = {
+	COCHRAN_MODEL_COMMANDER_TM, // model
+	24,         // address_bits
+	ENDIAN_WORD_BE,	// endian
+	9600,       // baudrate
+	4096,       // rbstream_size
+	0x146,      // cf_dive_count
+	0x158,      // cf_last_log
+	0xffffff,   // cf_last_interdive
+	0x15c,      // cf_serial_number
+	0x010000,   // rb_logbook_begin
+	0x01232b,   // rb_logbook_end
+	90,         // rb_logbook_entry_size
+	100,        // rb_logbook_entry_count
+	0x01232b,   // rb_profile_begin
+	0x018000,   // rb_profile_end
+	15,         // pt_fingerprint
+	4,          // fingerprint_size
+	0,          // pt_profile_pre
+	0,          // pt_profile_begin
+	90,         // pt_profile_end (Next begin pointer is the end)
+	20,         // pt_dive_number
+};
+
 // Cochran Commander pre-21000 s/n
 static const cochran_device_layout_t cochran_cmdr_1_device_layout = {
 	COCHRAN_MODEL_COMMANDER_PRE21000, // model
 	24,         // address_bits
 	ENDIAN_WORD_BE,  // endian
 	115200,     // baudrate
+	32768,      // rbstream_size
 	0x046,      // cf_dive_count
 	0x6c,       // cf_last_log
 	0x70,       // cf_last_interdive
@@ -137,6 +165,7 @@ static const cochran_device_layout_t cochran_cmdr_1_device_layout = {
 	28,         // pt_profile_pre
 	0,          // pt_profile_begin
 	128,        // pt_profile_end
+	68,         // pt_dive_number
 };
 
 
@@ -146,6 +175,7 @@ static const cochran_device_layout_t cochran_cmdr_device_layout = {
 	24,         // address_bits
 	ENDIAN_WORD_BE,  // endian
 	115200,     // baudrate
+	32768,      // rbstream_size
 	0x046,      // cf_dive_count
 	0x06C,      // cf_last_log
 	0x070,      // cf_last_interdive
@@ -161,6 +191,7 @@ static const cochran_device_layout_t cochran_cmdr_device_layout = {
 	30,         // pt_profile_pre
 	6,          // pt_profile_begin
 	128,        // pt_profile_end
+	70,         // pt_dive_number
 };
 
 // Cochran EMC-14
@@ -169,6 +200,7 @@ static const cochran_device_layout_t cochran_emc14_device_layout = {
 	32,         // address_bits
 	ENDIAN_LE,  // endian
 	806400,     // baudrate
+	65536,      // rbstream_size
 	0x0D2,      // cf_dive_count
 	0x13E,      // cf_last_log
 	0x142,      // cf_last_interdive
@@ -184,6 +216,7 @@ static const cochran_device_layout_t cochran_emc14_device_layout = {
 	30,         // pt_profile_pre
 	6,          // pt_profile_begin
 	256,        // pt_profile_end
+	86,         // pt_dive_number
 };
 
 // Cochran EMC-16
@@ -192,6 +225,7 @@ static const cochran_device_layout_t cochran_emc16_device_layout = {
 	32,         // address_bits
 	ENDIAN_LE,  // endian
 	806400,     // baudrate
+	65536,      // rbstream_size
 	0x0D2,      // cf_dive_count
 	0x13E,      // cf_last_log
 	0x142,      // cf_last_interdive
@@ -207,6 +241,7 @@ static const cochran_device_layout_t cochran_emc16_device_layout = {
 	30,         // pt_profile_pre
 	6,          // pt_profile_begin
 	256,        // pt_profile_end
+	86,         // pt_dive_number
 };
 
 // Cochran EMC-20
@@ -215,6 +250,7 @@ static const cochran_device_layout_t cochran_emc20_device_layout = {
 	32,         // address_bits
 	ENDIAN_LE,  // endian
 	806400,     // baudrate
+	65536,      // rbstream_size
 	0x0D2,      // cf_dive_count
 	0x13E,      // cf_last_log
 	0x142,      // cf_last_interdive
@@ -230,6 +266,7 @@ static const cochran_device_layout_t cochran_emc20_device_layout = {
 	30,         // pt_profile_pre
 	6,          // pt_profile_begin
 	256,        // pt_profile_end
+	86,         // pt_dive_number
 };
 
 
@@ -238,6 +275,7 @@ static unsigned int
 cochran_commander_get_model (cochran_commander_device_t *device)
 {
 	const cochran_commander_model_t models[] = {
+		{"\x0a""12", COCHRAN_MODEL_COMMANDER_TM},
 		{"\x11""21", COCHRAN_MODEL_COMMANDER_PRE21000},
 		{"\x11""22", COCHRAN_MODEL_COMMANDER_AIR_NITROX},
 		{"730",      COCHRAN_MODEL_EMC_14},
@@ -330,7 +368,7 @@ cochran_commander_packet (cochran_commander_device_t *device, dc_event_progress_
 		}
 	}
 
-	if (high_speed) {
+	if (high_speed && device->layout->baudrate != 9600) {
 		// Give the DC time to process the command.
 		dc_serial_sleep(device->port, 45);
 
@@ -399,18 +437,24 @@ cochran_commander_read_config (cochran_commander_device_t *device, dc_event_prog
 	dc_device_t *abstract = (dc_device_t *) device;
 	dc_status_t rc = DC_STATUS_SUCCESS;
 
-	// Read two 512 byte blocks into one 1024 byte buffer
-	for (unsigned int i = 0; i < 2; i++) {
-		const unsigned int len = size / 2;
+	if ((size % 512) != 0)
+		return DC_STATUS_INVALIDARGS;
 
+	// Read two 512 byte blocks into one 1024 byte buffer
+	unsigned int pages = size / 512;
+	for (unsigned int i = 0; i < pages; i++) {
 		unsigned char command[2] = {0x96, i};
-		rc = cochran_commander_packet(device, progress, command, sizeof(command), data + i * len, len, 0);
+		unsigned int command_size = sizeof(command);
+		if (device->layout->model == COCHRAN_MODEL_COMMANDER_TM)
+			command_size = 1;
+
+		rc = cochran_commander_packet(device, progress, command, command_size, data + i * 512, 512, 0);
 		if (rc != DC_STATUS_SUCCESS)
 			return rc;
 
 		dc_event_vendor_t vendor;
-		vendor.data = data + i * len;
-		vendor.size = len;
+		vendor.data = data + i * 512;
+		vendor.size = 512;
 		device_event_emit (abstract, DC_EVENT_VENDOR, &vendor);
 	}
 
@@ -444,15 +488,36 @@ cochran_commander_read (cochran_commander_device_t *device, dc_event_progress_t
 		break;
 	case 24:
 		// Commander uses 24 byte addressing
-		command[0] = 0x15;
-		command[1] = (address      ) & 0xff;
-		command[2] = (address >>  8) & 0xff;
-		command[3] = (address >> 16) & 0xff;
-		command[4] = (size         ) & 0xff;
-		command[5] = (size >>  8   ) & 0xff;
-		command[6] = (size >> 16   ) & 0xff;
-		command[7] = 0x04;
-		command_size = 8;
+		if (device->layout->baudrate == 9600) {
+			// This read command will return 32K bytes if asked to read
+			// 0 bytes. So we can allow a size of up to 0x10000 but if
+			// the user asks for 0 bytes we should just return success
+			// otherwise we'll end end up running past the buffer.
+			if (size > 0x10000)
+				return DC_STATUS_INVALIDARGS;
+			if (size == 0)
+				return DC_STATUS_SUCCESS;
+
+			// Older commander, use low-speed read command
+			command[0] = 0x05;
+			command[1] = (address      ) & 0xff;
+			command[2] = (address >>  8) & 0xff;
+			command[3] = (address >> 16) & 0xff;
+			command[4] = (size         ) & 0xff;
+			command[5] = (size >> 8    ) & 0xff;
+			command_size = 6;
+		} else {
+			// Newer commander with high-speed read command
+			command[0] = 0x15;
+			command[1] = (address      ) & 0xff;
+			command[2] = (address >>  8) & 0xff;
+			command[3] = (address >> 16) & 0xff;
+			command[4] = (size         ) & 0xff;
+			command[5] = (size >>  8   ) & 0xff;
+			command[6] = (size >> 16   ) & 0xff;
+			command[7] = 0x04;
+			command_size = 8;
+		}
 		break;
 	default:
 		return DC_STATUS_UNSUPPORTED;
@@ -473,31 +538,6 @@ cochran_commander_read (cochran_commander_device_t *device, dc_event_progress_t
 	return DC_STATUS_SUCCESS;
 }
 
-static unsigned int
-cochran_commander_read_retry (cochran_commander_device_t *device, dc_event_progress_t *progress, unsigned int address, unsigned char data[], unsigned int size)
-{
-	// Save the state of the progress events.
-	unsigned int saved = progress->current;
-
-	unsigned int nretries = 0;
-	dc_status_t rc = DC_STATUS_SUCCESS;
-	while ((rc = cochran_commander_read (device, progress, address, data, size)) != DC_STATUS_SUCCESS) {
-		// Automatically discard a corrupted packet,
-		// and request a new one.
-		if (rc != DC_STATUS_PROTOCOL && rc != DC_STATUS_TIMEOUT)
-			return rc;
-
-		// Abort if the maximum number of retries is reached.
-		if (nretries++ >= MAXRETRIES)
-			return rc;
-
-		// Restore the state of the progress events.
-		progress->current = saved;
-	}
-
-	return rc;
-}
-
 
 /*
  *  For corrupt dives the end-of-samples pointer is 0xFFFFFFFF
@@ -547,6 +587,8 @@ cochran_commander_profile_size(cochran_commander_device_t *device, cochran_data_
 static unsigned int
 cochran_commander_find_fingerprint(cochran_commander_device_t *device, cochran_data_t *data)
 {
+	unsigned int base = device->layout->rb_logbook_begin;
+
 	// We track profile ringbuffer usage to determine which dives have profile data
 	int profile_capacity_remaining = device->layout->rb_profile_end - device->layout->rb_profile_begin;
 
@@ -565,10 +607,13 @@ cochran_commander_find_fingerprint(cochran_commander_device_t *device, cochran_d
 
 	// Remove the pre-dive events that occur after the last dive
 	unsigned int rb_head_ptr = 0;
-	if (device->layout->endian == ENDIAN_WORD_BE)
-		rb_head_ptr = (array_uint32_word_be(data->config + device->layout->cf_last_log) & 0xfffff000) + 0x2000;
+	if (device->layout->model == COCHRAN_MODEL_COMMANDER_TM)
+		// TM uses SRAM and does not need to erase pages
+		rb_head_ptr = base + array_uint16_be(data->config + device->layout->cf_last_log);
+	else if (device->layout->endian == ENDIAN_WORD_BE)
+		rb_head_ptr = base + (array_uint32_word_be(data->config + device->layout->cf_last_log) & 0xfffff000) + 0x2000;
 	else
-		rb_head_ptr = (array_uint32_le(data->config + device->layout->cf_last_log) & 0xfffff000) + 0x2000;
+		rb_head_ptr = base + (array_uint32_le(data->config + device->layout->cf_last_log) & 0xfffff000) + 0x2000;
 
 	unsigned int head_dive = 0, tail_dive = 0;
 
@@ -582,13 +627,20 @@ cochran_commander_find_fingerprint(cochran_commander_device_t *device, cochran_d
 	}
 
 	unsigned int last_profile_idx = (device->layout->rb_logbook_entry_count + head_dive - 1) % device->layout->rb_logbook_entry_count;
-	unsigned int last_profile_end = array_uint32_le(data->logbook + last_profile_idx * device->layout->rb_logbook_entry_size + device->layout->pt_profile_end);
-	unsigned int last_profile_pre = 0xFFFFFFFF;
-
-	if (device->layout->endian == ENDIAN_WORD_BE)
-		last_profile_pre = array_uint32_word_be(data->config + device->layout->cf_last_log);
+	unsigned int last_profile_end = 0;
+	if (device->layout->model == COCHRAN_MODEL_COMMANDER_TM)
+		// There is no end pointer in this model and no inter-dive
+		// events. We could use profile_begin from the next dive but
+		// since this is the last dive, we'll use rb_head_ptr
+		last_profile_end = rb_head_ptr;
 	else
-		last_profile_pre = array_uint32_le(data->config + device->layout->cf_last_log);
+		last_profile_end = base + array_uint32_le(data->logbook + last_profile_idx * device->layout->rb_logbook_entry_size + device->layout->pt_profile_end);
+
+	unsigned int last_profile_pre = 0xFFFFFFFF;
+	if (device->layout->endian == ENDIAN_WORD_BE)
+		last_profile_pre = base + array_uint32_word_be(data->config + device->layout->cf_last_log);
+	else
+		last_profile_pre = base + array_uint32_le(data->config + device->layout->cf_last_log);
 
 	if (rb_head_ptr > last_profile_end)
 		profile_capacity_remaining -= rb_head_ptr - last_profile_end;
@@ -606,12 +658,13 @@ cochran_commander_find_fingerprint(cochran_commander_device_t *device, cochran_d
 			break;
 		}
 
-		unsigned int profile_pre = array_uint32_le(log_entry + device->layout->pt_profile_pre);
-		unsigned int profile_begin = array_uint32_le(log_entry + device->layout->pt_profile_begin);
-		unsigned int profile_end = array_uint32_le(log_entry + device->layout->pt_profile_end);
+		unsigned int profile_pre = 0;
+		if (device->layout->model == COCHRAN_MODEL_COMMANDER_TM)
+			profile_pre = base + array_uint16_le(log_entry + device->layout->pt_profile_pre);
+		else
+			profile_pre = base + array_uint32_le(log_entry + device->layout->pt_profile_pre);
 
 		unsigned int sample_size = cochran_commander_profile_size(device, data, idx, profile_pre, last_profile_pre);
-		unsigned int read_size = cochran_commander_profile_size(device, data, idx, profile_begin, profile_end);
 		last_profile_pre = profile_pre;
 
 		// Determine if sample exists
@@ -623,7 +676,7 @@ cochran_commander_find_fingerprint(cochran_commander_device_t *device, cochran_d
 				data->invalid_profile_dive_num = idx;
 			}
 			// Accumulate read size for progress bar
-			sample_read_size += read_size;
+			sample_read_size += sample_size;
 		}
 	}
 
@@ -631,69 +684,6 @@ cochran_commander_find_fingerprint(cochran_commander_device_t *device, cochran_d
 }
 
 
-
-static void
-cochran_commander_get_sample_parms(cochran_commander_device_t *device, cochran_data_t *data)
-{
-	dc_device_t *abstract = (dc_device_t *) device;
-	unsigned int pre_dive_offset = 0, end_dive_offset = 0;
-
-	unsigned int dive_count = 0;
-	if (data->dive_count < device->layout->rb_logbook_entry_count)
-		dive_count = data->dive_count;
-	else
-		dive_count = device->layout->rb_logbook_entry_count;
-
-	// Find lowest and highest offsets into sample data
-	unsigned int low_offset = 0xFFFFFFFF;
-	unsigned int high_offset = 0;
-
-	for (int i = data->fp_dive_num + 1; i < dive_count; i++) {
-		pre_dive_offset = array_uint32_le (data->logbook + i * device->layout->rb_logbook_entry_size
-				+ device->layout->pt_profile_pre);
-		end_dive_offset = array_uint32_le (data->logbook + i * device->layout->rb_logbook_entry_size
-				+ device->layout->pt_profile_end);
-
-		// Validate offsets, allow 0xFFFFFFF for end_dive_offset
-		// because we handle that as a special case.
-		if (pre_dive_offset < device->layout->rb_profile_begin ||
-			pre_dive_offset > device->layout->rb_profile_end) {
-			ERROR(abstract->context, "Invalid pre-dive offset (%08x) on dive %d.", pre_dive_offset, i);
-			continue;
-		}
-
-		if (end_dive_offset < device->layout->rb_profile_begin ||
-			(end_dive_offset > device->layout->rb_profile_end &&
-			end_dive_offset != 0xFFFFFFFF)) {
-			ERROR(abstract->context, "Invalid end-dive offset (%08x) on dive %d.", end_dive_offset, i);
-			continue;
-		}
-
-		// Check for ring buffer wrap-around.
-		if (pre_dive_offset > end_dive_offset)
-			break;
-
-		if (pre_dive_offset < low_offset)
-			low_offset = pre_dive_offset;
-		if (end_dive_offset > high_offset && end_dive_offset != 0xFFFFFFFF )
-			high_offset = end_dive_offset;
-	}
-
-	if (pre_dive_offset > end_dive_offset) {
-		high_offset = device->layout->rb_profile_end;
-		low_offset = device->layout->rb_profile_begin;
-		data->sample_data_offset = low_offset;
-		data->sample_size = high_offset - low_offset;
-	} else if (low_offset < 0xFFFFFFFF && high_offset > 0) {
-		data->sample_data_offset = low_offset;
-		data->sample_size = high_offset - data->sample_data_offset;
-	} else {
-		data->sample_data_offset = 0;
-		data->sample_size = 0;
-	}
-}
-
-
 dc_status_t
 cochran_commander_device_open (dc_device_t **out, dc_context_t *context, const char *name)
 {
@@ -735,6 +725,9 @@ cochran_commander_device_open (dc_device_t **out, dc_context_t *context, const c
 
 	unsigned int model = cochran_commander_get_model(device);
 	switch (model) {
+	case COCHRAN_MODEL_COMMANDER_TM:
+		device->layout = &cochran_cmdr_tm_device_layout;
+		break;
 	case COCHRAN_MODEL_COMMANDER_PRE21000:
 		device->layout = &cochran_cmdr_1_device_layout;
 		break;
@@ -815,6 +808,8 @@ cochran_commander_device_dump (dc_device_t *abstract, dc_buffer_t *buffer)
 	cochran_commander_device_t *device = (cochran_commander_device_t *) abstract;
 	dc_status_t rc = DC_STATUS_SUCCESS;
 	unsigned char config[1024];
+	unsigned int config_size = sizeof(config);
+	unsigned int size = device->layout->rb_profile_end - device->layout->rb_logbook_begin;
 
 	// Make sure buffer is good.
 	if (!dc_buffer_clear(buffer)) {
@@ -823,14 +818,17 @@ cochran_commander_device_dump (dc_device_t *abstract, dc_buffer_t *buffer)
 	}
 
 	// Reserve space
-	if (!dc_buffer_resize(buffer, device->layout->rb_profile_end)) {
+	if (!dc_buffer_resize(buffer, size)) {
 		ERROR(abstract->context, "Insufficient buffer space available.");
 		return DC_STATUS_NOMEMORY;
 	}
 
+	if (device->layout->model == COCHRAN_MODEL_COMMANDER_TM)
+		config_size = 512;
+
 	// Determine size for progress
 	dc_event_progress_t progress = EVENT_PROGRESS_INITIALIZER;
-	progress.maximum = sizeof(config) + device->layout->rb_profile_end;
+	progress.maximum = config_size + size;
 	device_event_emit (abstract, DC_EVENT_PROGRESS, &progress);
 
 	// Emit ID block
@@ -839,12 +837,12 @@ cochran_commander_device_dump (dc_device_t *abstract, dc_buffer_t *buffer)
 	vendor.size = sizeof (device->id);
 	device_event_emit (abstract, DC_EVENT_VENDOR, &vendor);
 
-	rc = cochran_commander_read_config (device, &progress, config, sizeof(config));
+	rc = cochran_commander_read_config (device, &progress, config, config_size);
 	if (rc != DC_STATUS_SUCCESS)
 		return rc;
 
-	// Read the sample data, from 0 to sample end will include logbook
-	rc = cochran_commander_read (device, &progress, 0, dc_buffer_get_data(buffer), device->layout->rb_profile_end);
+	// Read the sample data, logbook and sample data are contiguous
+	rc = cochran_commander_read (device, &progress, device->layout->rb_logbook_begin, dc_buffer_get_data(buffer), size);
 	if (rc != DC_STATUS_SUCCESS) {
 		ERROR (abstract->context, "Failed to read the sample data.");
 		return rc;
@@ -860,6 +858,7 @@ cochran_commander_device_foreach (dc_device_t *abstract, dc_dive_callback_t call
 	cochran_commander_device_t *device = (cochran_commander_device_t *) abstract;
 	const cochran_device_layout_t *layout = device->layout;
 	dc_status_t status = DC_STATUS_SUCCESS;
+	dc_rbstream_t *rbstream = NULL;
 
 	cochran_data_t data;
 	data.logbook = NULL;
@@ -868,6 +867,10 @@ cochran_commander_device_foreach (dc_device_t *abstract, dc_dive_callback_t call
 	unsigned int max_config = sizeof(data.config);
 	unsigned int max_logbook = layout->rb_logbook_end - layout->rb_logbook_begin;
 	unsigned int max_sample = layout->rb_profile_end - layout->rb_profile_begin;
+	unsigned int base = device->layout->rb_logbook_begin;
+
+	if (device->layout->model == COCHRAN_MODEL_COMMANDER_TM)
+		max_config = 512;
 
 	// setup progress indication
 	dc_event_progress_t progress = EVENT_PROGRESS_INITIALIZER;
@@ -882,7 +885,7 @@ cochran_commander_device_foreach (dc_device_t *abstract, dc_dive_callback_t call
 
 	// Read config
 	dc_status_t rc = DC_STATUS_SUCCESS;
-	rc = cochran_commander_read_config(device, &progress, data.config, sizeof(data.config));
+	rc = cochran_commander_read_config(device, &progress, data.config, max_config);
 	if (rc != DC_STATUS_SUCCESS)
 		return rc;
 
@@ -892,9 +895,11 @@ cochran_commander_device_foreach (dc_device_t *abstract, dc_dive_callback_t call
 	else
 		data.dive_count = array_uint16_be (data.config + layout->cf_dive_count);
 
-	if (data.dive_count == 0)
+	if (data.dive_count == 0) {
 		// No dives to read
+		WARNING(abstract->context, "This dive computer has no recorded dives.");
 		return DC_STATUS_SUCCESS;
+	}
 
 	if (data.dive_count > layout->rb_logbook_entry_count) {
 		data.logbook_size = layout->rb_logbook_entry_count * layout->rb_logbook_entry_size;
@@ -914,7 +919,7 @@ cochran_commander_device_foreach (dc_device_t *abstract, dc_dive_callback_t call
 	}
 
 	// Request log book
-	rc = cochran_commander_read(device, &progress, 0, data.logbook, data.logbook_size);
+	rc = cochran_commander_read(device, &progress, layout->rb_logbook_begin, data.logbook, data.logbook_size);
 	if (rc != DC_STATUS_SUCCESS) {
 		status = rc;
 		goto error;
@@ -922,12 +927,11 @@ cochran_commander_device_foreach (dc_device_t *abstract, dc_dive_callback_t call
 
 	// Locate fingerprint, recent dive with invalid profile and calc read size
 	unsigned int profile_read_size = cochran_commander_find_fingerprint(device, &data);
+
 	// Update progress indicator with new maximum
 	progress.maximum -= (max_sample - profile_read_size);
 	device_event_emit (abstract, DC_EVENT_PROGRESS, &progress);
 
-	cochran_commander_get_sample_parms(device, &data);
-
 	// Emit a device info event.
 	dc_event_devinfo_t devinfo;
 	devinfo.model = layout->model;
@@ -957,6 +961,19 @@ cochran_commander_device_foreach (dc_device_t *abstract, dc_dive_callback_t call
 	// Number of dives to read
 	dive_count = (layout->rb_logbook_entry_count + head_dive - tail_dive) % layout->rb_logbook_entry_count;
 
+	unsigned int last_start_address = 0;
+	if (layout->endian == ENDIAN_WORD_BE)
+		last_start_address = base + array_uint32_word_be(data.config + layout->cf_last_log );
+	else
+		last_start_address = base + array_uint32_le(data.config + layout->cf_last_log );
+
+	// Create the ringbuffer stream.
+	status = dc_rbstream_new (&rbstream, abstract, 1, layout->rbstream_size, layout->rb_profile_begin, layout->rb_profile_end, last_start_address);
+	if (status != DC_STATUS_SUCCESS) {
+		ERROR (abstract->context, "Failed to create the ringbuffer stream.");
+		goto error;
+	}
+
 	int invalid_profile_flag = 0;
 
 	// Loop through each dive
@@ -965,21 +982,39 @@ cochran_commander_device_foreach (dc_device_t *abstract, dc_dive_callback_t call
 
 		unsigned char *log_entry = data.logbook + idx * layout->rb_logbook_entry_size;
 
-		unsigned int sample_start_address = array_uint32_le (log_entry + layout->pt_profile_begin);
-		unsigned int sample_end_address = array_uint32_le (log_entry + layout->pt_profile_end);
+		unsigned int sample_start_address = 0;
+		unsigned int sample_end_address = 0;
+		if (layout->model == COCHRAN_MODEL_COMMANDER_TM) {
+			sample_start_address = base + array_uint16_le (log_entry + layout->pt_profile_begin);
+			sample_end_address = last_start_address;
+			// Commander TM has SRAM which seems to randomize when they lose power for too long
+			// Check for bad entries.
+			if (sample_start_address < layout->rb_profile_begin || sample_start_address > layout->rb_profile_end ||
+				sample_end_address < layout->rb_profile_begin || sample_end_address > layout->rb_profile_end ||
+				array_uint16_le(log_entry + layout->pt_dive_number) % layout->rb_logbook_entry_count != idx) {
+				ERROR(abstract->context, "Corrupt dive (%d).", idx);
+				continue;
+			}
+		} else {
+			sample_start_address = base + array_uint32_le (log_entry + layout->pt_profile_begin);
+			sample_end_address = base + array_uint32_le (log_entry + layout->pt_profile_end);
+		}
 
-		int sample_size = 0;
+		int sample_size = 0, pre_size = 0;
 
 		// Determine if profile exists
 		if (idx == data.invalid_profile_dive_num)
 			invalid_profile_flag = 1;
 
-		if (!invalid_profile_flag)
+		if (!invalid_profile_flag) {
 			sample_size = cochran_commander_profile_size(device, &data, idx, sample_start_address, sample_end_address);
+			pre_size = cochran_commander_profile_size(device, &data, idx, sample_end_address, last_start_address);
+			last_start_address = sample_start_address;
+		}
 
 		// Build dive blob
 		unsigned int dive_size = layout->rb_logbook_entry_size + sample_size;
-		unsigned char *dive = (unsigned char *) malloc(dive_size);
+		unsigned char *dive = (unsigned char *) malloc(dive_size + pre_size);
 		if (dive == NULL) {
 			status = DC_STATUS_NOMEMORY;
 			goto error;
@@ -989,37 +1024,12 @@ cochran_commander_device_foreach (dc_device_t *abstract, dc_dive_callback_t call
 
 		// Read profile data
 		if (sample_size) {
-			if (sample_end_address == 0xFFFFFFFF)
-				// Corrupt dive, guess the end address
-				sample_end_address = cochran_commander_guess_sample_end_address(device, &data, idx);
-
-			if (sample_start_address <= sample_end_address) {
-				rc = cochran_commander_read_retry (device, &progress, sample_start_address, dive + layout->rb_logbook_entry_size, sample_size);
-				if (rc != DC_STATUS_SUCCESS) {
-					ERROR (abstract->context, "Failed to read the sample data.");
-					status = rc;
-					free(dive);
-					goto error;
-				}
-			} else {
-				// It wrapped the buffer, copy two sections
-				unsigned int size = layout->rb_profile_end - sample_start_address;
-
-				rc = cochran_commander_read_retry (device, &progress, sample_start_address, dive + layout->rb_logbook_entry_size, size);
-				if (rc != DC_STATUS_SUCCESS) {
-					ERROR (abstract->context, "Failed to read the sample data.");
-					status = rc;
-					free(dive);
-					goto error;
-				}
-
-				rc = cochran_commander_read_retry (device, &progress, layout->rb_profile_begin, dive + layout->rb_logbook_entry_size + size, sample_end_address - layout->rb_profile_begin);
-				if (rc != DC_STATUS_SUCCESS) {
-					ERROR (abstract->context, "Failed to read the sample data.");
-					status = rc;
-					free(dive);
-					goto error;
-				}
+			rc = dc_rbstream_read(rbstream, &progress, dive + layout->rb_logbook_entry_size, sample_size + pre_size);
+			if (rc != DC_STATUS_SUCCESS) {
+				ERROR (abstract->context, "Failed to read the sample data.");
+				status = rc;
+				free(dive);
+				goto error;
 			}
 		}
 
@@ -1032,6 +1042,7 @@ cochran_commander_device_foreach (dc_device_t *abstract, dc_dive_callback_t call
 	}
 
 error:
+	dc_rbstream_free(rbstream);
 	free(data.logbook);
 	return status;
 }
diff --git a/src/cochran_commander_parser.c b/src/cochran_commander_parser.c
index 5a0ad55..12e8b42 100644
--- a/src/cochran_commander_parser.c
+++ b/src/cochran_commander_parser.c
@@ -31,11 +31,12 @@
 
 #define C_ARRAY_SIZE(array) (sizeof (array) / sizeof *(array))
 
-#define COCHRAN_MODEL_COMMANDER_PRE21000 0
-#define COCHRAN_MODEL_COMMANDER_AIR_NITROX 1
-#define COCHRAN_MODEL_EMC_14 2
-#define COCHRAN_MODEL_EMC_16 3
-#define COCHRAN_MODEL_EMC_20 4
+#define COCHRAN_MODEL_COMMANDER_TM 0
+#define COCHRAN_MODEL_COMMANDER_PRE21000 1
+#define COCHRAN_MODEL_COMMANDER_AIR_NITROX 2
+#define COCHRAN_MODEL_EMC_14 3
+#define COCHRAN_MODEL_EMC_16 4
+#define COCHRAN_MODEL_EMC_20 5
 
 // Cochran time stamps start at Jan 1, 1992
 #define COCHRAN_EPOCH 694242000
@@ -43,6 +44,7 @@
 #define UNSUPPORTED 0xFFFFFFFF
 
 typedef enum cochran_sample_format_t {
+	SAMPLE_TM,
 	SAMPLE_CMDR,
 	SAMPLE_EMC,
 } cochran_sample_format_t;
@@ -58,6 +60,7 @@ typedef struct cochran_parser_layout_t {
 	cochran_sample_format_t format;
 	unsigned int headersize;
 	unsigned int samplesize;
+	unsigned int pt_sample_interval;
 	cochran_date_encoding_t date_encoding;
 	unsigned int datetime;
 	unsigned int pt_profile_begin;
@@ -113,10 +116,36 @@ static const dc_parser_vtable_t cochran_commander_parser_vtable = {
 	NULL /* destroy */
 };
 
+static const cochran_parser_layout_t cochran_cmdr_tm_parser_layout = {
+	SAMPLE_TM,   // format
+	90,          // headersize
+	1,           // samplesize
+	72,          // pt_sample_interval
+	DATE_ENCODING_TICKS, // date_encoding
+	15,          // datetime, 4 bytes
+	0,           // pt_profile_begin, 4 bytes
+	UNSUPPORTED, // water_conductivity, 1 byte, 0=low(fresh), 2=high(sea)
+	0,           // pt_profile_pre, 4 bytes
+	83,          // start_temp, 1 byte, F
+	UNSUPPORTED, // start_depth, 2 bytes, /4=ft
+	20,          // dive_number, 2 bytes
+	UNSUPPORTED, // altitude, 1 byte, /4=kilofeet
+	UNSUPPORTED, // pt_profile_end, 4 bytes
+	UNSUPPORTED, // end_temp, 1 byte F
+	57,          // divetime, 2 bytes, minutes
+	49,          // max_depth, 2 bytes, /4=ft
+	51,          // avg_depth, 2 bytes, /4=ft
+	74,          // oxygen, 4 bytes (2 of) 2 bytes, /256=%
+	UNSUPPORTED, // helium, 4 bytes (2 of) 2 bytes, /256=%
+	82,          // min_temp, 1 byte, /2+20=F
+	UNSUPPORTED, // max_temp, 1 byte, /2+20=F
+};
+
 static const cochran_parser_layout_t cochran_cmdr_1_parser_layout = {
-	SAMPLE_CMDR, // type
+	SAMPLE_CMDR, // format
 	256,         // headersize
 	2,           // samplesize
+	UNSUPPORTED, // pt_sample_interval
 	DATE_ENCODING_TICKS, // date_encoding
 	8,           // datetime, 4 bytes
 	0,           // pt_profile_begin, 4 bytes
@@ -138,9 +167,10 @@ static const cochran_parser_layout_t cochran_cmdr_1_parser_layout = {
 };
 
 static const cochran_parser_layout_t cochran_cmdr_parser_layout = {
-	SAMPLE_CMDR, // type
+	SAMPLE_CMDR, // format
 	256,         // headersize
 	2,           // samplesize
+	UNSUPPORTED, // pt_sample_interval
 	DATE_ENCODING_MSDHYM, // date_encoding
 	0,           // datetime, 6 bytes
 	6,           // pt_profile_begin, 4 bytes
@@ -162,9 +192,10 @@ static const cochran_parser_layout_t cochran_cmdr_parser_layout = {
 };
 
 static const cochran_parser_layout_t cochran_emc_parser_layout = {
-	SAMPLE_EMC,  // type
+	SAMPLE_EMC,  // format
 	512,         // headersize
 	3,           // samplesize
+	UNSUPPORTED, // pt_sample_interval
 	DATE_ENCODING_SMHDMY, // date_encoding
 	0,           // datetime, 6 bytes
 	6,           // pt_profile_begin, 4 bytes
@@ -190,16 +221,20 @@ static const cochran_events_t cochran_events[] = {
 	{0xA9, 1, SAMPLE_EVENT_SURFACE,  SAMPLE_FLAGS_END},   // Exited PDI mode
 	{0xAB, 5, SAMPLE_EVENT_NONE,     SAMPLE_FLAGS_NONE},  // Ceiling decrease
 	{0xAD, 5, SAMPLE_EVENT_NONE,     SAMPLE_FLAGS_NONE},  // Ceiling increase
+	{0xB5, 1, SAMPLE_EVENT_AIRTIME,  SAMPLE_FLAGS_BEGIN}, // Air < 5 mins deco
 	{0xBD, 1, SAMPLE_EVENT_NONE,     SAMPLE_FLAGS_NONE},  // Switched to nomal PO2 setting
+	{0xBE, 1, SAMPLE_EVENT_NONE,     SAMPLE_FLAGS_NONE},  // Ceiling > 60 ft
 	{0xC0, 1, SAMPLE_EVENT_NONE,     SAMPLE_FLAGS_NONE},  // Switched to FO2 21% mode
 	{0xC1, 1, SAMPLE_EVENT_ASCENT,   SAMPLE_FLAGS_BEGIN}, // Ascent rate greater than limit
 	{0xC2, 1, SAMPLE_EVENT_NONE,     SAMPLE_FLAGS_NONE},  // Low battery warning
 	{0xC3, 1, SAMPLE_EVENT_OLF,      SAMPLE_FLAGS_NONE},  // CNS Oxygen toxicity warning
 	{0xC4, 1, SAMPLE_EVENT_MAXDEPTH, SAMPLE_FLAGS_NONE},  // Depth exceeds user set point
 	{0xC5, 1, SAMPLE_EVENT_NONE,     SAMPLE_FLAGS_BEGIN}, // Entered decompression mode
+	{0xC7, 1, SAMPLE_EVENT_VIOLATION,SAMPLE_FLAGS_BEGIN}, // Entered Gauge mode (e.g. locked out)
 	{0xC8, 1, SAMPLE_EVENT_PO2,      SAMPLE_FLAGS_BEGIN}, // PO2 too high
 	{0xCC, 1, SAMPLE_EVENT_NONE,     SAMPLE_FLAGS_BEGIN}, // Low Cylinder 1 pressure
 	{0xCE, 1, SAMPLE_EVENT_NONE,     SAMPLE_FLAGS_BEGIN}, // Non-decompression warning
+	{0xCF, 1, SAMPLE_EVENT_OLF,      SAMPLE_FLAGS_BEGIN}, // O2 Toxicity
 	{0xCD, 1, SAMPLE_EVENT_NONE,     SAMPLE_FLAGS_NONE},  // Switched to deco blend
 	{0xD0, 1, SAMPLE_EVENT_WORKLOAD, SAMPLE_FLAGS_BEGIN}, // Breathing rate alarm
 	{0xD3, 1, SAMPLE_EVENT_NONE,     SAMPLE_FLAGS_NONE},  // Low gas 1 flow rate
@@ -334,6 +369,11 @@ cochran_commander_parser_create (dc_parser_t **out, dc_context_t *context, unsig
 	parser->model = model;
 
 	switch (model) {
+	case COCHRAN_MODEL_COMMANDER_TM:
+		parser->layout = &cochran_cmdr_tm_parser_layout;
+		parser->events = NULL;	// No inter-dive events on this model
+		parser->nevents = 0;
+		break;
 	case COCHRAN_MODEL_COMMANDER_PRE21000:
 		parser->layout = &cochran_cmdr_1_parser_layout;
 		parser->events = cochran_cmdr_event_bytes;
@@ -395,6 +435,7 @@ cochran_commander_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *dat
 			datetime->day = data[layout->datetime + 2];
 			datetime->month = data[layout->datetime + 5];
 			datetime->year = data[layout->datetime + 4] + (data[layout->datetime + 4] > 91 ? 1900 : 2000);
+			datetime->timezone = DC_TIMEZONE_NONE;
 			break;
 		case DATE_ENCODING_SMHDMY:
 			datetime->second = data[layout->datetime + 0];
@@ -403,6 +444,7 @@ cochran_commander_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *dat
 			datetime->day = data[layout->datetime + 3];
 			datetime->month = data[layout->datetime + 4];
 			datetime->year = data[layout->datetime + 5] + (data[layout->datetime + 5] > 91 ? 1900 : 2000);
+			datetime->timezone = DC_TIMEZONE_NONE;
 			break;
 		case DATE_ENCODING_TICKS:
 			ts = array_uint32_le(data + layout->datetime) + COCHRAN_EPOCH;
@@ -440,6 +482,8 @@ cochran_commander_parser_get_field (dc_parser_t *abstract, dc_field_type_t type,
 			*((unsigned int*) value) = (data[layout->min_temp] / 2.0 + 20 - 32) / 1.8;
 			break;
 		case DC_FIELD_TEMPERATURE_MAXIMUM:
+			if (layout->max_temp == UNSUPPORTED)
+				return DC_STATUS_UNSUPPORTED;
 			if (data[layout->max_temp] == 0xFF)
 				return DC_STATUS_UNSUPPORTED;
 			*((unsigned int*) value) = (data[layout->max_temp] / 2.0 + 20 - 32) / 1.8;
@@ -484,6 +528,8 @@ cochran_commander_parser_get_field (dc_parser_t *abstract, dc_field_type_t type,
 			// for density assume
 			//  0 = 1000kg/m³, 2 = 1025kg/m³
 			// and other values are linear
+			if (layout->water_conductivity == UNSUPPORTED)
+				return DC_STATUS_UNSUPPORTED;
 			if ((data[layout->water_conductivity] & 0x3) == 0)
 				water->type = DC_WATER_FRESH;
 			else
@@ -493,6 +539,8 @@ cochran_commander_parser_get_field (dc_parser_t *abstract, dc_field_type_t type,
 		case DC_FIELD_ATMOSPHERIC:
 			// Cochran measures air pressure and stores it as altitude.
 			// Convert altitude (measured in 1/4 kilofeet) back to pressure.
+			if (layout->altitude == UNSUPPORTED)
+				return DC_STATUS_UNSUPPORTED;
 			*(double *) value = ATM / BAR * pow(1 - 0.0000225577 * data[layout->altitude] * 250.0 * FEET, 5.25588);
 			break;
 		default:
@@ -504,8 +552,117 @@ cochran_commander_parser_get_field (dc_parser_t *abstract, dc_field_type_t type,
 }
 
 
+/*
+ * Parse early Commander computers
+ */
 static dc_status_t
-cochran_commander_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_t callback, void *userdata)
+cochran_commander_parser_samples_foreach_tm (dc_parser_t *abstract, dc_sample_callback_t callback, void *userdata)
+{
+	cochran_commander_parser_t *parser = (cochran_commander_parser_t *) abstract;
+	const cochran_parser_layout_t *layout = parser->layout;
+	const unsigned char *data = abstract->data;
+	const unsigned char *samples = data + layout->headersize;
+
+	if (abstract->size < layout->headersize)
+		return DC_STATUS_DATAFORMAT;
+
+	unsigned int size = abstract->size - layout->headersize;
+	unsigned int sample_interval = data[layout->pt_sample_interval];
+
+	dc_sample_value_t sample = {0};
+	unsigned int time = 0, last_sample_time = 0;
+	unsigned int offset = 2;
+	unsigned int deco_ceiling = 0;
+
+	unsigned int temp = samples[0];	// Half degrees F
+	unsigned int depth = samples[1];	// Half feet
+
+	last_sample_time = sample.time = time;
+	if (callback) callback (DC_SAMPLE_TIME, sample, userdata);
+
+	sample.depth = (depth / 2.0) * FEET;
+	if (callback) callback (DC_SAMPLE_DEPTH, sample, userdata);
+
+	sample.temperature = (temp / 2.0 - 32.0) / 1.8;
+	if (callback) callback (DC_SAMPLE_TEMPERATURE, sample, userdata);
+
+	sample.gasmix = 0;
+	if (callback) callback(DC_SAMPLE_GASMIX, sample, userdata);
+
+	while (offset < size) {
+		const unsigned char *s = samples + offset;
+
+		sample.time = time;
+		if (last_sample_time != sample.time) {
+			// We haven't issued this time yet.
+			last_sample_time = sample.time;
+			if (callback) callback (DC_SAMPLE_TIME, sample, userdata);
+		}
+
+		if (*s & 0x80) {
+			// Event or temperate change byte
+			if (*s & 0x60) {
+				// Event byte
+				switch (*s) {
+				case 0xC5:  // Deco obligation begins
+					break;
+				case 0xD8:  // Deco obligation ends
+					break;
+				case 0xAB:  // Decrement ceiling (deeper)
+					deco_ceiling += 10; // feet
+
+					sample.deco.type = DC_DECO_DECOSTOP;
+					sample.deco.time = 60; // We don't know the duration
+					sample.deco.depth = deco_ceiling * FEET;
+					if (callback) callback(DC_SAMPLE_DECO, sample, userdata);
+					break;
+				case 0xAD:  // Increment ceiling (shallower)
+					deco_ceiling -= 10; // feet
+
+					sample.deco.type = DC_DECO_DECOSTOP;
+					sample.deco.depth = deco_ceiling * FEET;
+					sample.deco.time = 60; // We don't know the duration
+					if (callback) callback(DC_SAMPLE_DECO, sample, userdata);
+					break;
+				default:
+					cochran_commander_handle_event(parser, s[0], callback, userdata);
+					break;
+				}
+			} else {
+				// Temp change
+				if (*s & 0x10)
+					temp -= (*s & 0x0f);
+				else
+					temp += (*s & 0x0f);
+				sample.temperature = (temp / 2.0 - 32.0) / 1.8;
+				if (callback) callback (DC_SAMPLE_TEMPERATURE, sample, userdata);
+			}
+
+			offset++;
+			continue;
+		}
+
+		// Depth sample
+		if (s[0] & 0x40)
+			depth -= s[0] & 0x3f;
+		else
+			depth += s[0] & 0x3f;
+
+		sample.depth = (depth / 2.0) * FEET;
+		if (callback) callback (DC_SAMPLE_DEPTH, sample, userdata);
+
+		offset++;
+		time += sample_interval;
+	}
+	return DC_STATUS_SUCCESS;
+}
+
+
+/*
+ * Parse Commander I (Pre-21000 s/n), II and EMC computers
+ */
+static dc_status_t
+cochran_commander_parser_samples_foreach_emc (dc_parser_t *abstract, dc_sample_callback_t callback, void *userdata)
 {
 	cochran_commander_parser_t *parser = (cochran_commander_parser_t *) abstract;
 	const cochran_parser_layout_t *layout = parser->layout;
@@ -720,3 +877,15 @@ cochran_commander_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callb
 
 	return DC_STATUS_SUCCESS;
 }
+
+
+static dc_status_t
+cochran_commander_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_t callback, void *userdata)
+{
+	cochran_commander_parser_t *parser = (cochran_commander_parser_t *) abstract;
+
+	if (parser->model == COCHRAN_MODEL_COMMANDER_TM)
+		return cochran_commander_parser_samples_foreach_tm (abstract, callback, userdata);
+	else
+		return cochran_commander_parser_samples_foreach_emc (abstract, callback, userdata);
+}
diff --git a/src/cressi_edy.c b/src/cressi_edy.c
index 226f32f..68e13fc 100644
--- a/src/cressi_edy.c
+++ b/src/cressi_edy.c
@@ -75,6 +75,7 @@ static const dc_device_vtable_t cressi_edy_device_vtable = {
 	NULL, /* write */
 	cressi_edy_device_dump, /* dump */
 	cressi_edy_device_foreach, /* foreach */
+	NULL, /* timesync */
 	cressi_edy_device_close /* close */
 };
 
diff --git a/src/cressi_edy_parser.c b/src/cressi_edy_parser.c
index c9e1d91..eaf55c3 100644
--- a/src/cressi_edy_parser.c
+++ b/src/cressi_edy_parser.c
@@ -115,6 +115,7 @@ cressi_edy_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datetime)
 		datetime->hour = bcd2dec (p[14]);
 		datetime->minute = bcd2dec (p[15]);
 		datetime->second = 0;
+		datetime->timezone = DC_TIMEZONE_NONE;
 	}
 
 	return DC_STATUS_SUCCESS;
diff --git a/src/cressi_leonardo.c b/src/cressi_leonardo.c
index 5c1dd29..f21a223 100644
--- a/src/cressi_leonardo.c
+++ b/src/cressi_leonardo.c
@@ -67,6 +67,7 @@ static const dc_device_vtable_t cressi_leonardo_device_vtable = {
 	NULL, /* write */
 	cressi_leonardo_device_dump, /* dump */
 	cressi_leonardo_device_foreach, /* foreach */
+	NULL, /* timesync */
 	cressi_leonardo_device_close /* close */
 };
 
@@ -448,32 +449,25 @@ cressi_leonardo_extract_dives (dc_device_t *abstract, const unsigned char data[]
 	if (size < SZ_MEMORY)
 		return DC_STATUS_DATAFORMAT;
 
-	// Locate the most recent dive.
-	// The device maintains an internal counter which is incremented for every
-	// dive, and the current value at the time of the dive is stored in the
-	// dive header. Thus the most recent dive will have the highest value.
-	unsigned int count = 0;
-	unsigned int latest = 0;
-	unsigned int maximum = 0;
-	for (unsigned int i = 0; i < RB_LOGBOOK_COUNT; ++i) {
-		unsigned int offset = RB_LOGBOOK_BEGIN + i * RB_LOGBOOK_SIZE;
+	// Get the number of dives.
+	//unsigned int ndives = array_uint16_le(data + 0x62);
 
-		// Ignore uninitialized header entries.
-		if (array_isequal (data + offset, RB_LOGBOOK_SIZE, 0xFF))
-			break;
+	// Get the logbook pointer.
+	unsigned int last = array_uint16_le(data + 0x64);
+	if (last < RB_LOGBOOK_BEGIN || last > RB_LOGBOOK_END ||
+		((last - RB_LOGBOOK_BEGIN) % RB_LOGBOOK_SIZE) != 0) {
+		ERROR (context, "Invalid logbook pointer (0x%04x).", last);
+		return DC_STATUS_DATAFORMAT;
+	}
 
-		// Get the internal dive number.
-		unsigned int current = array_uint16_le (data + offset);
-		if (current == 0xFFFF) {
-			WARNING (context, "Unexpected internal dive number found.");
-			break;
-		}
-		if (current > maximum) {
-			maximum = current;
-			latest = i;
-		}
+	// Convert to an index.
+	unsigned int latest = (last - RB_LOGBOOK_BEGIN) / RB_LOGBOOK_SIZE;
 
-		count++;
+	// Get the profile pointer.
+	unsigned int eop = array_uint16_le(data + 0x66);
+	if (eop < RB_PROFILE_BEGIN || last > RB_PROFILE_END) {
+		ERROR (context, "Invalid profile pointer (0x%04x).", eop);
+		return DC_STATUS_DATAFORMAT;
 	}
 
 	unsigned char *buffer = (unsigned char *) malloc (RB_LOGBOOK_SIZE + RB_PROFILE_END - RB_PROFILE_BEGIN);
@@ -482,12 +476,16 @@ cressi_leonardo_extract_dives (dc_device_t *abstract, const unsigned char data[]
 		return DC_STATUS_NOMEMORY;
 	}
 
-	unsigned int previous = 0;
+	unsigned int previous = eop;
 	unsigned int remaining = RB_PROFILE_END - RB_PROFILE_BEGIN;
-	for (unsigned int i = 0; i < count; ++i) {
+	for (unsigned int i = 0; i < RB_LOGBOOK_COUNT; ++i) {
 		unsigned int idx = (latest + RB_LOGBOOK_COUNT - i) % RB_LOGBOOK_COUNT;
 		unsigned int offset = RB_LOGBOOK_BEGIN + idx * RB_LOGBOOK_SIZE;
 
+		// Ignore uninitialized header entries.
+		if (array_isequal (data + offset, RB_LOGBOOK_SIZE, 0xFF))
+			break;
+
 		// Get the ringbuffer pointers.
 		unsigned int header = array_uint16_le (data + offset + 2);
 		unsigned int footer = array_uint16_le (data + offset + 4);
diff --git a/src/cressi_leonardo_parser.c b/src/cressi_leonardo_parser.c
index 6032376..d7cf0de 100644
--- a/src/cressi_leonardo_parser.c
+++ b/src/cressi_leonardo_parser.c
@@ -46,7 +46,7 @@ static dc_status_t cressi_leonardo_parser_samples_foreach (dc_parser_t *abstract
 
 static const dc_parser_vtable_t cressi_leonardo_parser_vtable = {
 	sizeof(cressi_leonardo_parser_t),
-	DC_FAMILY_CRESSI_EDY,
+	DC_FAMILY_CRESSI_LEONARDO,
 	cressi_leonardo_parser_set_data, /* set_data */
 	cressi_leonardo_parser_get_datetime, /* datetime */
 	cressi_leonardo_parser_get_field, /* fields */
@@ -100,6 +100,7 @@ cressi_leonardo_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datet
 		datetime->hour = p[11];
 		datetime->minute = p[12];
 		datetime->second = 0;
+		datetime->timezone = DC_TIMEZONE_NONE;
 	}
 
 	return DC_STATUS_SUCCESS;
diff --git a/src/datetime.c b/src/datetime.c
index 9d07f8c..3ceed42 100644
--- a/src/datetime.c
+++ b/src/datetime.c
@@ -61,6 +61,47 @@ dc_gmtime_r (const time_t *t, struct tm *tm)
 #endif
 }
 
+static time_t
+dc_timegm (struct tm *tm)
+{
+#if defined(HAVE_TIMEGM)
+	return timegm (tm);
+#elif defined (HAVE__MKGMTIME)
+	return _mkgmtime (tm);
+#else
+	static const unsigned int mdays[] = {
+		0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
+	};
+
+	if (tm == NULL ||
+		tm->tm_mon  < 0 || tm->tm_mon  > 11 ||
+		tm->tm_mday < 1 || tm->tm_mday > 31 ||
+		tm->tm_hour < 0 || tm->tm_hour > 23 ||
+		tm->tm_min  < 0 || tm->tm_min  > 59 ||
+		tm->tm_sec  < 0 || tm->tm_sec  > 60)
+		return (time_t) -1;
+
+	/* Number of leap days since 1970-01-01. */
+	int year = tm->tm_year + 1900 - (tm->tm_mon < 2);
+	int leapdays =
+		((year / 4) - (year / 100) + (year / 400)) -
+		((1969 / 4) - (1969 / 100) + (1969 / 400));
+
+	time_t result = 0;
+	result += (tm->tm_year - 70) * 365;
+	result += leapdays;
+	result += mdays[tm->tm_mon];
+	result += tm->tm_mday - 1;
+	result *= 24;
+	result += tm->tm_hour;
+	result *= 60;
+	result += tm->tm_min;
+	result *= 60;
+	result += tm->tm_sec;
+	return result;
+#endif
+}
+
 dc_ticks_t
 dc_datetime_now (void)
 {
@@ -72,11 +113,23 @@ dc_datetime_localtime (dc_datetime_t *result,
                        dc_ticks_t ticks)
 {
 	time_t t = ticks;
+	int offset = 0;
 
 	struct tm tm;
 	if (dc_localtime_r (&t, &tm) == NULL)
 		return NULL;
 
+#ifdef HAVE_STRUCT_TM_TM_GMTOFF
+	offset = tm.tm_gmtoff;
+#else
+	struct tm tmp = tm;
+	time_t t_local = dc_timegm (&tmp);
+	if (t_local == (time_t) -1)
+		return NULL;
+
+	offset = t_local - t;
+#endif
+
 	if (result) {
 		result->year = tm.tm_year + 1900;
 		result->month = tm.tm_mon + 1;
@@ -84,6 +137,7 @@ dc_datetime_localtime (dc_datetime_t *result,
 		result->hour = tm.tm_hour;
 		result->minute = tm.tm_min;
 		result->second = tm.tm_sec;
+		result->timezone = offset;
 	}
 
 	return result;
@@ -106,6 +160,7 @@ dc_datetime_gmtime (dc_datetime_t *result,
 		result->hour = tm.tm_hour;
 		result->minute = tm.tm_min;
 		result->second = tm.tm_sec;
+		result->timezone = 0;
 	}
 
 	return result;
@@ -124,7 +179,15 @@ dc_datetime_mktime (const dc_datetime_t *dt)
 	tm.tm_hour = dt->hour;
 	tm.tm_min = dt->minute;
 	tm.tm_sec = dt->second;
-	tm.tm_isdst = -1;
+	tm.tm_isdst = 0;
 
-	return mktime (&tm);
+	time_t t = dc_timegm (&tm);
+	if (t == (time_t) -1)
+		return t;
+
+	if (dt->timezone != DC_TIMEZONE_NONE) {
+		t -= dt->timezone;
+	}
+
+	return t;
 }
diff --git a/src/descriptor.c b/src/descriptor.c
index 30e4ced..d4bab60 100644
--- a/src/descriptor.c
+++ b/src/descriptor.c
@@ -23,9 +23,9 @@
 #include "config.h"
 #endif
 
-#if defined(HAVE_LIBUSB) && !defined(__APPLE__)
+#if defined(HAVE_HIDAPI)
 #define USBHID
-#elif defined(HAVE_HIDAPI)
+#elif defined(HAVE_LIBUSB) && !defined(__APPLE__)
 #define USBHID
 #endif
 
@@ -219,6 +219,7 @@ static const dc_descriptor_t g_descriptors[] = {
 	{"Aqualung", "i750TC",              DC_FAMILY_OCEANIC_ATOM2, 0x455A},  // FTDI
 	{"Aqualung", "i450T",               DC_FAMILY_OCEANIC_ATOM2, 0x4641},  // FTDI
 	{"Aqualung", "i550",                DC_FAMILY_OCEANIC_ATOM2, 0x4642},  // FTDI
+	{"Aqualung", "i200",                DC_FAMILY_OCEANIC_ATOM2, 0x4646},  // FTDI
 	/* Mares Nemo */
 	{"Mares", "Nemo",         DC_FAMILY_MARES_NEMO, 0},
 	{"Mares", "Nemo Steel",   DC_FAMILY_MARES_NEMO, 0},
@@ -256,8 +257,8 @@ static const dc_descriptor_t g_descriptors[] = {
 	{"Heinrichs Weikamp", "OSTC 2",     DC_FAMILY_HW_OSTC3, 0x13},  // FTDI
 	{"Heinrichs Weikamp", "OSTC 2",     DC_FAMILY_HW_OSTC3, 0x1B},  // FTDI
 	{"Heinrichs Weikamp", "OSTC 3",     DC_FAMILY_HW_OSTC3, 0x0A},  // FTDI
-	{"Heinrichs Weikamp", "OSTC 3+",    DC_FAMILY_HW_OSTC3, 0x13},  // FTDI // BT
-	{"Heinrichs Weikamp", "OSTC 3+",    DC_FAMILY_HW_OSTC3, 0x1A},  // FTDI // BT
+	{"Heinrichs Weikamp", "OSTC Plus",  DC_FAMILY_HW_OSTC3, 0x13},  // FTDI // BT
+	{"Heinrichs Weikamp", "OSTC Plus",  DC_FAMILY_HW_OSTC3, 0x1A},  // FTDI // BT
 	{"Heinrichs Weikamp", "OSTC 4",     DC_FAMILY_HW_OSTC3, 0x3B},  // BT
 	{"Heinrichs Weikamp", "OSTC cR",    DC_FAMILY_HW_OSTC3, 0x05},  // FTDI
 	{"Heinrichs Weikamp", "OSTC cR",    DC_FAMILY_HW_OSTC3, 0x07},  // FTDI
@@ -316,11 +317,12 @@ static const dc_descriptor_t g_descriptors[] = {
 	{"DiveSystem", "iDive2 Deep",    DC_FAMILY_DIVESYSTEM_IDIVE, 0x44},
 	{"DiveSystem", "iDive2 Tech+",   DC_FAMILY_DIVESYSTEM_IDIVE, 0x45},
 	/* Cochran Commander */
-	{"Cochran", "Commander I",	DC_FAMILY_COCHRAN_COMMANDER, 0},
-	{"Cochran", "Commander II",	DC_FAMILY_COCHRAN_COMMANDER, 1},
-	{"Cochran", "EMC-14",		DC_FAMILY_COCHRAN_COMMANDER, 2},
-	{"Cochran", "EMC-16",		DC_FAMILY_COCHRAN_COMMANDER, 3},
-	{"Cochran", "EMC-20H",		DC_FAMILY_COCHRAN_COMMANDER, 4},
+	{"Cochran", "Commander TM", DC_FAMILY_COCHRAN_COMMANDER, 0},
+	{"Cochran", "Commander I",  DC_FAMILY_COCHRAN_COMMANDER, 1},
+	{"Cochran", "Commander II", DC_FAMILY_COCHRAN_COMMANDER, 2},
+	{"Cochran", "EMC-14",       DC_FAMILY_COCHRAN_COMMANDER, 3},
+	{"Cochran", "EMC-16",       DC_FAMILY_COCHRAN_COMMANDER, 4},
+	{"Cochran", "EMC-20H",      DC_FAMILY_COCHRAN_COMMANDER, 5},
 };
 
 typedef struct dc_descriptor_iterator_t {
diff --git a/src/device-private.h b/src/device-private.h
index dcf0b96..7ca6610 100644
--- a/src/device-private.h
+++ b/src/device-private.h
@@ -71,6 +71,8 @@ struct dc_device_vtable_t {
 
 	dc_status_t (*foreach) (dc_device_t *device, dc_dive_callback_t callback, void *userdata);
 
+	dc_status_t (*timesync) (dc_device_t *device, const dc_datetime_t *datetime);
+
 	dc_status_t (*close) (dc_device_t *device);
 };
 
diff --git a/src/device.c b/src/device.c
index 9a92966..0a9e2ba 100644
--- a/src/device.c
+++ b/src/device.c
@@ -370,6 +370,19 @@ dc_device_foreach (dc_device_t *device, dc_dive_callback_t callback, void *userd
 }
 
 
+dc_status_t
+dc_device_timesync (dc_device_t *device, const dc_datetime_t *datetime)
+{
+	if (device == NULL)
+		return DC_STATUS_UNSUPPORTED;
+
+	if (device->vtable->timesync == NULL)
+		return DC_STATUS_UNSUPPORTED;
+
+	return device->vtable->timesync (device, datetime);
+}
+
+
 dc_status_t
 dc_device_close (dc_device_t *device)
 {
diff --git a/src/diverite_nitekq.c b/src/diverite_nitekq.c
index 205115a..8c8c442 100644
--- a/src/diverite_nitekq.c
+++ b/src/diverite_nitekq.c
@@ -69,6 +69,7 @@ static const dc_device_vtable_t diverite_nitekq_device_vtable = {
 	NULL, /* write */
 	diverite_nitekq_device_dump, /* dump */
 	diverite_nitekq_device_foreach, /* foreach */
+	NULL, /* timesync */
 	diverite_nitekq_device_close /* close */
 };
 
diff --git a/src/diverite_nitekq_parser.c b/src/diverite_nitekq_parser.c
index 6c7a05f..dce40d8 100644
--- a/src/diverite_nitekq_parser.c
+++ b/src/diverite_nitekq_parser.c
@@ -118,6 +118,7 @@ diverite_nitekq_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datet
 		datetime->hour = p[3];
 		datetime->minute = p[4];
 		datetime->second = p[5];
+		datetime->timezone = DC_TIMEZONE_NONE;
 	}
 
 	return DC_STATUS_SUCCESS;
diff --git a/src/divesystem_idive.c b/src/divesystem_idive.c
index d26e2b4..8a8f1ae 100644
--- a/src/divesystem_idive.c
+++ b/src/divesystem_idive.c
@@ -86,6 +86,7 @@ static const dc_device_vtable_t divesystem_idive_device_vtable = {
 	NULL, /* write */
 	NULL, /* dump */
 	divesystem_idive_device_foreach, /* foreach */
+	NULL, /* timesync */
 	divesystem_idive_device_close /* close */
 };
 
diff --git a/src/divesystem_idive_parser.c b/src/divesystem_idive_parser.c
index 473dc57..ff9f480 100644
--- a/src/divesystem_idive_parser.c
+++ b/src/divesystem_idive_parser.c
@@ -173,6 +173,7 @@ divesystem_idive_parser_get_field (dc_parser_t *abstract, dc_field_type_t type,
 	}
 
 	dc_gasmix_t *gasmix = (dc_gasmix_t *) value;
+	dc_salinity_t *water = (dc_salinity_t *) value;
 
 	if (value) {
 		switch (type) {
@@ -191,7 +192,15 @@ divesystem_idive_parser_get_field (dc_parser_t *abstract, dc_field_type_t type,
 			gasmix->nitrogen = 1.0 - gasmix->oxygen - gasmix->helium;
 			break;
 		case DC_FIELD_ATMOSPHERIC:
-			*((double *) value) = array_uint16_le (data + 11) / 1000.0;
+			if (parser->model >= IX3M_EASY) {
+				*((double *) value) = array_uint16_le (data + 11) / 10000.0;
+			} else {
+				*((double *) value) = array_uint16_le (data + 11) / 1000.0;
+			}
+			break;
+		case DC_FIELD_SALINITY:
+			water->type = data[34] == 0 ? DC_WATER_SALT : DC_WATER_FRESH;
+			water->density = 0.0;
 			break;
 		case DC_FIELD_DIVEMODE:
 			if (parser->divemode == 0xFFFFFFFF)
diff --git a/src/hw_frog.c b/src/hw_frog.c
index d8b89ca..83ee998 100644
--- a/src/hw_frog.c
+++ b/src/hw_frog.c
@@ -61,6 +61,7 @@ typedef struct hw_frog_device_t {
 
 static dc_status_t hw_frog_device_set_fingerprint (dc_device_t *abstract, const unsigned char data[], unsigned int size);
 static dc_status_t hw_frog_device_foreach (dc_device_t *abstract, dc_dive_callback_t callback, void *userdata);
+static dc_status_t hw_frog_device_timesync (dc_device_t *abstract, const dc_datetime_t *datetime);
 static dc_status_t hw_frog_device_close (dc_device_t *abstract);
 
 static const dc_device_vtable_t hw_frog_device_vtable = {
@@ -71,6 +72,7 @@ static const dc_device_vtable_t hw_frog_device_vtable = {
 	NULL, /* write */
 	NULL, /* dump */
 	hw_frog_device_foreach, /* foreach */
+	hw_frog_device_timesync, /* timesync */
 	hw_frog_device_close /* close */
 };
 
@@ -482,14 +484,11 @@ hw_frog_device_foreach (dc_device_t *abstract, dc_dive_callback_t callback, void
 }
 
 
-dc_status_t
-hw_frog_device_clock (dc_device_t *abstract, const dc_datetime_t *datetime)
+static dc_status_t
+hw_frog_device_timesync (dc_device_t *abstract, const dc_datetime_t *datetime)
 {
 	hw_frog_device_t *device = (hw_frog_device_t *) abstract;
 
-	if (!ISINSTANCE (abstract))
-		return DC_STATUS_INVALIDARGS;
-
 	if (datetime == NULL) {
 		ERROR (abstract->context, "Invalid parameter specified.");
 		return DC_STATUS_INVALIDARGS;
diff --git a/src/hw_ostc.c b/src/hw_ostc.c
index 3f46603..87c2b1d 100644
--- a/src/hw_ostc.c
+++ b/src/hw_ostc.c
@@ -70,6 +70,7 @@ typedef struct hw_ostc_firmware_t {
 static dc_status_t hw_ostc_device_set_fingerprint (dc_device_t *abstract, const unsigned char data[], unsigned int size);
 static dc_status_t hw_ostc_device_dump (dc_device_t *abstract, dc_buffer_t *buffer);
 static dc_status_t hw_ostc_device_foreach (dc_device_t *abstract, dc_dive_callback_t callback, void *userdata);
+static dc_status_t hw_ostc_device_timesync (dc_device_t *abstract, const dc_datetime_t *datetime);
 static dc_status_t hw_ostc_device_close (dc_device_t *abstract);
 
 static const dc_device_vtable_t hw_ostc_device_vtable = {
@@ -80,6 +81,7 @@ static const dc_device_vtable_t hw_ostc_device_vtable = {
 	NULL, /* write */
 	hw_ostc_device_dump, /* dump */
 	hw_ostc_device_foreach, /* foreach */
+	hw_ostc_device_timesync, /* timesync */
 	hw_ostc_device_close /* close */
 };
 
@@ -377,15 +379,12 @@ hw_ostc_device_md2hash (dc_device_t *abstract, unsigned char data[], unsigned in
 }
 
 
-dc_status_t
-hw_ostc_device_clock (dc_device_t *abstract, const dc_datetime_t *datetime)
+static dc_status_t
+hw_ostc_device_timesync (dc_device_t *abstract, const dc_datetime_t *datetime)
 {
 	dc_status_t status = DC_STATUS_SUCCESS;
 	hw_ostc_device_t *device = (hw_ostc_device_t *) abstract;
 
-	if (!ISINSTANCE (abstract))
-		return DC_STATUS_INVALIDARGS;
-
 	if (datetime == NULL) {
 		ERROR (abstract->context, "Invalid parameter specified.");
 		return DC_STATUS_INVALIDARGS;
diff --git a/src/hw_ostc3.c b/src/hw_ostc3.c
index e7b7d9e..a1a5efd 100644
--- a/src/hw_ostc3.c
+++ b/src/hw_ostc3.c
@@ -129,6 +129,7 @@ static dc_status_t hw_ostc3_device_read (dc_device_t *abstract, unsigned int add
 static dc_status_t hw_ostc3_device_write (dc_device_t *abstract, unsigned int address, const unsigned char data[], unsigned int size);
 static dc_status_t hw_ostc3_device_dump (dc_device_t *abstract, dc_buffer_t *buffer);
 static dc_status_t hw_ostc3_device_foreach (dc_device_t *abstract, dc_dive_callback_t callback, void *userdata);
+static dc_status_t hw_ostc3_device_timesync (dc_device_t *abstract, const dc_datetime_t *datetime);
 static dc_status_t hw_ostc3_device_close (dc_device_t *abstract);
 
 static const dc_device_vtable_t hw_ostc3_device_vtable = {
@@ -139,6 +140,7 @@ static const dc_device_vtable_t hw_ostc3_device_vtable = {
 	hw_ostc3_device_write, /* write */
 	hw_ostc3_device_dump, /* dump */
 	hw_ostc3_device_foreach, /* foreach */
+	hw_ostc3_device_timesync, /* timesync */
 	hw_ostc3_device_close /* close */
 };
 
@@ -801,14 +803,11 @@ hw_ostc3_device_foreach (dc_device_t *abstract, dc_dive_callback_t callback, voi
 }
 
 
-dc_status_t
-hw_ostc3_device_clock (dc_device_t *abstract, const dc_datetime_t *datetime)
+static dc_status_t
+hw_ostc3_device_timesync (dc_device_t *abstract, const dc_datetime_t *datetime)
 {
 	hw_ostc3_device_t *device = (hw_ostc3_device_t *) abstract;
 
-	if (!ISINSTANCE (abstract))
-		return DC_STATUS_INVALIDARGS;
-
 	if (datetime == NULL) {
 		ERROR (abstract->context, "Invalid parameter specified.");
 		return DC_STATUS_INVALIDARGS;
diff --git a/src/hw_ostc_parser.c b/src/hw_ostc_parser.c
index 2b97cf9..78c2c5d 100644
--- a/src/hw_ostc_parser.c
+++ b/src/hw_ostc_parser.c
@@ -432,6 +432,7 @@ hw_ostc_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datetime)
 	dt.hour   = p[3];
 	dt.minute = p[4];
 	dt.second = 0;
+	dt.timezone = DC_TIMEZONE_NONE;
 
 	if (version == 0x24) {
 		if (datetime)
@@ -443,8 +444,10 @@ hw_ostc_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datetime)
 
 		ticks -= divetime;
 
-		if (!dc_datetime_localtime (datetime, ticks))
+		if (!dc_datetime_gmtime (datetime, ticks))
 			return DC_STATUS_DATAFORMAT;
+
+		datetime->timezone = DC_TIMEZONE_NONE;
 	}
 
 	return DC_STATUS_SUCCESS;
diff --git a/src/libdivecomputer.symbols b/src/libdivecomputer.symbols
index ba12d56..62f13c3 100644
--- a/src/libdivecomputer.symbols
+++ b/src/libdivecomputer.symbols
@@ -57,6 +57,7 @@ dc_device_read
 dc_device_set_cancel
 dc_device_set_events
 dc_device_set_fingerprint
+dc_device_timesync
 dc_device_write
 
 oceanic_atom2_device_version
@@ -80,19 +81,16 @@ suunto_eon_device_write_name
 suunto_vyper2_device_version
 suunto_vyper2_device_reset_maxdepth
 hw_ostc_device_md2hash
-hw_ostc_device_clock
 hw_ostc_device_eeprom_read
 hw_ostc_device_eeprom_write
 hw_ostc_device_reset
 hw_ostc_device_screenshot
 hw_ostc_device_fwupdate
 hw_frog_device_version
-hw_frog_device_clock
 hw_frog_device_display
 hw_frog_device_customtext
 hw_ostc3_device_version
 hw_ostc3_device_hardware
-hw_ostc3_device_clock
 hw_ostc3_device_display
 hw_ostc3_device_customtext
 hw_ostc3_device_config_read
diff --git a/src/mares_darwin.c b/src/mares_darwin.c
index 9ac56ba..4b1bc24 100644
--- a/src/mares_darwin.c
+++ b/src/mares_darwin.c
@@ -70,6 +70,7 @@ static const dc_device_vtable_t mares_darwin_device_vtable = {
 	NULL, /* write */
 	mares_darwin_device_dump, /* dump */
 	mares_darwin_device_foreach, /* foreach */
+	NULL, /* timesync */
 	mares_darwin_device_close /* close */
 };
 
diff --git a/src/mares_darwin_parser.c b/src/mares_darwin_parser.c
index 1201ec6..ba0382f 100644
--- a/src/mares_darwin_parser.c
+++ b/src/mares_darwin_parser.c
@@ -118,6 +118,7 @@ mares_darwin_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datetime
 		datetime->hour   = p[4];
 		datetime->minute = p[5];
 		datetime->second = 0;
+		datetime->timezone = DC_TIMEZONE_NONE;
 	}
 
 	return DC_STATUS_SUCCESS;
diff --git a/src/mares_iconhd.c b/src/mares_iconhd.c
index 3a73968..e945e9f 100644
--- a/src/mares_iconhd.c
+++ b/src/mares_iconhd.c
@@ -87,6 +87,7 @@ static const dc_device_vtable_t mares_iconhd_device_vtable = {
 	NULL, /* write */
 	mares_iconhd_device_dump, /* dump */
 	mares_iconhd_device_foreach, /* foreach */
+	NULL, /* timesync */
 	mares_iconhd_device_close /* close */
 };
 
diff --git a/src/mares_iconhd_parser.c b/src/mares_iconhd_parser.c
index 0c45a15..76324f3 100644
--- a/src/mares_iconhd_parser.c
+++ b/src/mares_iconhd_parser.c
@@ -329,6 +329,7 @@ mares_iconhd_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datetime
 		datetime->day    = array_uint16_le (p + 4);
 		datetime->month  = array_uint16_le (p + 6) + 1;
 		datetime->year   = array_uint16_le (p + 8) + 1900;
+		datetime->timezone = DC_TIMEZONE_NONE;
 	}
 
 	return DC_STATUS_SUCCESS;
diff --git a/src/mares_nemo.c b/src/mares_nemo.c
index 2ec3588..c73c24b 100644
--- a/src/mares_nemo.c
+++ b/src/mares_nemo.c
@@ -62,6 +62,7 @@ static const dc_device_vtable_t mares_nemo_device_vtable = {
 	NULL, /* write */
 	mares_nemo_device_dump, /* dump */
 	mares_nemo_device_foreach, /* foreach */
+	NULL, /* timesync */
 	mares_nemo_device_close /* close */
 };
 
diff --git a/src/mares_nemo_parser.c b/src/mares_nemo_parser.c
index 9a6cbfd..c0ab03b 100644
--- a/src/mares_nemo_parser.c
+++ b/src/mares_nemo_parser.c
@@ -200,6 +200,7 @@ mares_nemo_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datetime)
 		datetime->hour   = p[3];
 		datetime->minute = p[4];
 		datetime->second = 0;
+		datetime->timezone = DC_TIMEZONE_NONE;
 	}
 
 	return DC_STATUS_SUCCESS;
diff --git a/src/mares_puck.c b/src/mares_puck.c
index fc8e00d..b220f54 100644
--- a/src/mares_puck.c
+++ b/src/mares_puck.c
@@ -57,6 +57,7 @@ static const dc_device_vtable_t mares_puck_device_vtable = {
 	NULL, /* write */
 	mares_puck_device_dump, /* dump */
 	mares_puck_device_foreach, /* foreach */
+	NULL, /* timesync */
 	mares_puck_device_close /* close */
 };
 
diff --git a/src/oceanic_atom2.c b/src/oceanic_atom2.c
index da19e7f..bae6537 100644
--- a/src/oceanic_atom2.c
+++ b/src/oceanic_atom2.c
@@ -74,6 +74,7 @@ static const oceanic_common_device_vtable_t oceanic_atom2_device_vtable = {
 		oceanic_atom2_device_write, /* write */
 		oceanic_common_device_dump, /* dump */
 		oceanic_common_device_foreach, /* foreach */
+		NULL, /* timesync */
 		oceanic_atom2_device_close /* close */
 	},
 	oceanic_common_device_logbook,
@@ -107,6 +108,7 @@ static const oceanic_common_version_t oceanic_atom2a_version[] = {
 	{"PROPLUS2 \0\0 512K"},
 	{"OCEGEO20 \0\0 512K"},
 	{"OCE GEO R\0\0 512K"},
+	{"AQUAI200 \0\0 512K"},
 };
 
 static const oceanic_common_version_t oceanic_atom2b_version[] = {
diff --git a/src/oceanic_atom2_parser.c b/src/oceanic_atom2_parser.c
index 137adbc..f527c7e 100644
--- a/src/oceanic_atom2_parser.c
+++ b/src/oceanic_atom2_parser.c
@@ -86,6 +86,7 @@
 #define I750TC      0x455A
 #define I450T       0x4641
 #define I550        0x4642
+#define I200        0x4646
 
 #define NORMAL   0
 #define GAUGE    1
@@ -157,7 +158,8 @@ oceanic_atom2_parser_create (dc_parser_t **out, dc_context_t *context, unsigned
 		model == OCS || model == PROPLUS3 ||
 		model == A300 || model == MANTA ||
 		model == INSIGHT2 || model == ZEN ||
-		model == I300 || model == I550) {
+		model == I300 || model == I550 ||
+		model == I200) {
 		parser->headersize -= PAGESIZE;
 	} else if (model == VT4 || model == VT41) {
 		parser->headersize += PAGESIZE;
@@ -270,6 +272,7 @@ oceanic_atom2_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datetim
 		case COMPUMASK:
 		case INSIGHT2:
 		case I300:
+		case I200:
 			datetime->year   = ((p[3] & 0xE0) >> 1) + (p[4] & 0x0F) + 2000;
 			datetime->month  = (p[4] & 0xF0) >> 4;
 			datetime->day    = p[3] & 0x1F;
@@ -325,6 +328,7 @@ oceanic_atom2_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datetim
 			break;
 		}
 		datetime->second = 0;
+		datetime->timezone = DC_TIMEZONE_NONE;
 
 		// Convert to a 24-hour clock.
 		datetime->hour %= 12;
@@ -704,7 +708,8 @@ oceanic_atom2_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_
 		parser->model == ELEMENT2 || parser->model == VEO20 ||
 		parser->model == A300 || parser->model == ZEN ||
 		parser->model == GEO || parser->model == GEO20 ||
-		parser->model == MANTA || parser->model == I300) {
+		parser->model == MANTA || parser->model == I300 ||
+		parser->model == I200) {
 		have_pressure = 0;
 	}
 
@@ -858,7 +863,8 @@ oceanic_atom2_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_
 					parser->model == VEO30 || parser->model == OC1A ||
 					parser->model == OC1B || parser->model == OC1C ||
 					parser->model == OCI || parser->model == A300 ||
-					parser->model == I450T || parser->model == I300) {
+					parser->model == I450T || parser->model == I300 ||
+					parser->model == I200) {
 					temperature = data[offset + 3];
 				} else if (parser->model == OCS || parser->model == TX1) {
 					temperature = data[offset + 1];
@@ -925,7 +931,8 @@ oceanic_atom2_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_
 				parser->model == VEO30 || parser->model == OC1A ||
 				parser->model == OC1B || parser->model == OC1C ||
 				parser->model == OCI || parser->model == A300 ||
-				parser->model == I450T || parser->model == I300)
+				parser->model == I450T || parser->model == I300 ||
+				parser->model == I200)
 				depth = (data[offset + 4] + (data[offset + 5] << 8)) & 0x0FFF;
 			else if (parser->model == ATOM1)
 				depth = data[offset + 3] * 16;
@@ -972,6 +979,10 @@ oceanic_atom2_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_
 				decostop = (data[offset + 5] & 0xF0) >> 4;
 				decotime = array_uint16_le(data + offset + 4) & 0x03FF;
 				have_deco = 1;
+			} else if (parser->model == I200) {
+				decostop = (data[offset + 7] & 0xF0) >> 4;
+				decotime = array_uint16_le(data + offset + 6) & 0x0FFF;
+				have_deco = 1;
 			}
 			if (have_deco) {
 				if (decostop) {
diff --git a/src/oceanic_veo250.c b/src/oceanic_veo250.c
index d47c532..b6021dd 100644
--- a/src/oceanic_veo250.c
+++ b/src/oceanic_veo250.c
@@ -56,6 +56,7 @@ static const oceanic_common_device_vtable_t oceanic_veo250_device_vtable = {
 		NULL, /* write */
 		oceanic_common_device_dump, /* dump */
 		oceanic_common_device_foreach, /* foreach */
+		NULL, /* timesync */
 		oceanic_veo250_device_close /* close */
 	},
 	oceanic_common_device_logbook,
diff --git a/src/oceanic_veo250_parser.c b/src/oceanic_veo250_parser.c
index ba69723..a3acf57 100644
--- a/src/oceanic_veo250_parser.c
+++ b/src/oceanic_veo250_parser.c
@@ -121,6 +121,7 @@ oceanic_veo250_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *dateti
 		datetime->hour   = p[3];
 		datetime->minute = p[2];
 		datetime->second = 0;
+		datetime->timezone = DC_TIMEZONE_NONE;
 
 		if (parser->model == VEO200 || parser->model == VEO250)
 			datetime->year += 3;
diff --git a/src/oceanic_vtpro.c b/src/oceanic_vtpro.c
index 2e86f5f..cc09892 100644
--- a/src/oceanic_vtpro.c
+++ b/src/oceanic_vtpro.c
@@ -68,6 +68,7 @@ static const oceanic_common_device_vtable_t oceanic_vtpro_device_vtable = {
 		NULL, /* write */
 		oceanic_common_device_dump, /* dump */
 		oceanic_common_device_foreach, /* foreach */
+		NULL, /* timesync */
 		oceanic_vtpro_device_close /* close */
 	},
 	oceanic_vtpro_device_logbook,
diff --git a/src/oceanic_vtpro_parser.c b/src/oceanic_vtpro_parser.c
index 9c85854..894b626 100644
--- a/src/oceanic_vtpro_parser.c
+++ b/src/oceanic_vtpro_parser.c
@@ -135,6 +135,7 @@ oceanic_vtpro_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datetim
 		}
 		datetime->minute = bcd2dec (p[0]);
 		datetime->second = 0;
+		datetime->timezone = DC_TIMEZONE_NONE;
 
 		// Convert to a 24-hour clock.
 		datetime->hour %= 12;
diff --git a/src/reefnet_sensus.c b/src/reefnet_sensus.c
index 94d7a7e..37c343a 100644
--- a/src/reefnet_sensus.c
+++ b/src/reefnet_sensus.c
@@ -57,6 +57,7 @@ static const dc_device_vtable_t reefnet_sensus_device_vtable = {
 	NULL, /* write */
 	reefnet_sensus_device_dump, /* dump */
 	reefnet_sensus_device_foreach, /* foreach */
+	NULL, /* timesync */
 	reefnet_sensus_device_close /* close */
 };
 
diff --git a/src/reefnet_sensuspro.c b/src/reefnet_sensuspro.c
index bf88801..4df3c07 100644
--- a/src/reefnet_sensuspro.c
+++ b/src/reefnet_sensuspro.c
@@ -56,6 +56,7 @@ static const dc_device_vtable_t reefnet_sensuspro_device_vtable = {
 	NULL, /* write */
 	reefnet_sensuspro_device_dump, /* dump */
 	reefnet_sensuspro_device_foreach, /* foreach */
+	NULL, /* timesync */
 	reefnet_sensuspro_device_close /* close */
 };
 
diff --git a/src/reefnet_sensusultra.c b/src/reefnet_sensusultra.c
index f28dbb2..fba7511 100644
--- a/src/reefnet_sensusultra.c
+++ b/src/reefnet_sensusultra.c
@@ -65,6 +65,7 @@ static const dc_device_vtable_t reefnet_sensusultra_device_vtable = {
 	NULL, /* write */
 	reefnet_sensusultra_device_dump, /* dump */
 	reefnet_sensusultra_device_foreach, /* foreach */
+	NULL, /* timesync */
 	reefnet_sensusultra_device_close /* close */
 };
 
diff --git a/src/scubapro_g2.c b/src/scubapro_g2.c
index 33ecfc4..9a0c336 100644
--- a/src/scubapro_g2.c
+++ b/src/scubapro_g2.c
@@ -51,6 +51,7 @@ static const dc_device_vtable_t scubapro_g2_device_vtable = {
 	NULL, /* write */
 	scubapro_g2_device_dump, /* dump */
 	scubapro_g2_device_foreach, /* foreach */
+	NULL, /* timesync */
 	scubapro_g2_device_close /* close */
 };
 
diff --git a/src/shearwater_petrel.c b/src/shearwater_petrel.c
index 79f167d..7558c54 100644
--- a/src/shearwater_petrel.c
+++ b/src/shearwater_petrel.c
@@ -56,6 +56,7 @@ static const dc_device_vtable_t shearwater_petrel_device_vtable = {
 	NULL, /* write */
 	NULL, /* dump */
 	shearwater_petrel_device_foreach, /* foreach */
+	NULL, /* timesync */
 	shearwater_petrel_device_close /* close */
 };
 
diff --git a/src/shearwater_predator.c b/src/shearwater_predator.c
index 0e7a0d3..42a579b 100644
--- a/src/shearwater_predator.c
+++ b/src/shearwater_predator.c
@@ -57,6 +57,7 @@ static const dc_device_vtable_t shearwater_predator_device_vtable = {
 	NULL, /* write */
 	shearwater_predator_device_dump, /* dump */
 	shearwater_predator_device_foreach, /* foreach */
+	NULL, /* timesync */
 	shearwater_predator_device_close /* close */
 };
 
diff --git a/src/shearwater_predator_parser.c b/src/shearwater_predator_parser.c
index 6d4a3ec..992169c 100644
--- a/src/shearwater_predator_parser.c
+++ b/src/shearwater_predator_parser.c
@@ -200,6 +200,8 @@ shearwater_predator_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *d
 	if (!dc_datetime_gmtime (datetime, ticks))
 		return DC_STATUS_DATAFORMAT;
 
+	datetime->timezone = DC_TIMEZONE_NONE;
+
 	return DC_STATUS_SUCCESS;
 }
 
diff --git a/src/suunto_d9.c b/src/suunto_d9.c
index 2908792..56f8c40 100644
--- a/src/suunto_d9.c
+++ b/src/suunto_d9.c
@@ -58,6 +58,7 @@ static const suunto_common2_device_vtable_t suunto_d9_device_vtable = {
 		suunto_common2_device_write, /* write */
 		suunto_common2_device_dump, /* dump */
 		suunto_common2_device_foreach, /* foreach */
+		NULL, /* timesync */
 		suunto_d9_device_close /* close */
 	},
 	suunto_d9_device_packet
diff --git a/src/suunto_d9_parser.c b/src/suunto_d9_parser.c
index deb3ec1..5404997 100644
--- a/src/suunto_d9_parser.c
+++ b/src/suunto_d9_parser.c
@@ -320,6 +320,7 @@ suunto_d9_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datetime)
 			datetime->month  = p[5];
 			datetime->day    = p[6];
 		}
+		datetime->timezone = DC_TIMEZONE_NONE;
 	}
 
 	return DC_STATUS_SUCCESS;
diff --git a/src/suunto_eon.c b/src/suunto_eon.c
index ce9ce83..2875654 100644
--- a/src/suunto_eon.c
+++ b/src/suunto_eon.c
@@ -51,6 +51,7 @@ static const dc_device_vtable_t suunto_eon_device_vtable = {
 	NULL, /* write */
 	suunto_eon_device_dump, /* dump */
 	suunto_eon_device_foreach, /* foreach */
+	NULL, /* timesync */
 	suunto_eon_device_close /* close */
 };
 
diff --git a/src/suunto_eon_parser.c b/src/suunto_eon_parser.c
index 066c997..2106c69 100644
--- a/src/suunto_eon_parser.c
+++ b/src/suunto_eon_parser.c
@@ -178,6 +178,7 @@ suunto_eon_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datetime)
 			datetime->minute = bcd2dec (p[4]);
 		}
 		datetime->second = 0;
+		datetime->timezone = DC_TIMEZONE_NONE;
 	}
 
 	return DC_STATUS_SUCCESS;
diff --git a/src/suunto_eonsteel.c b/src/suunto_eonsteel.c
index c381668..7267ac8 100644
--- a/src/suunto_eonsteel.c
+++ b/src/suunto_eonsteel.c
@@ -81,6 +81,7 @@ static const dc_device_vtable_t suunto_eonsteel_device_vtable = {
 	NULL, /* write */
 	NULL, /* dump */
 	suunto_eonsteel_device_foreach, /* foreach */
+	NULL, /* timesync */
 	suunto_eonsteel_device_close /* close */
 };
 
diff --git a/src/suunto_eonsteel_parser.c b/src/suunto_eonsteel_parser.c
index fefaad2..f385bc9 100644
--- a/src/suunto_eonsteel_parser.c
+++ b/src/suunto_eonsteel_parser.c
@@ -1071,7 +1071,11 @@ suunto_eonsteel_parser_get_datetime(dc_parser_t *parser, dc_datetime_t *datetime
 	if (parser->size < 4)
 		return DC_STATUS_UNSUPPORTED;
 
-	dc_datetime_gmtime(datetime, array_uint32_le(parser->data));
+	if (!dc_datetime_gmtime(datetime, array_uint32_le(parser->data)))
+		return DC_STATUS_DATAFORMAT;
+
+	datetime->timezone = DC_TIMEZONE_NONE;
+
 	return DC_STATUS_SUCCESS;
 }
 
diff --git a/src/suunto_solution.c b/src/suunto_solution.c
index c708114..cb2481d 100644
--- a/src/suunto_solution.c
+++ b/src/suunto_solution.c
@@ -54,6 +54,7 @@ static const dc_device_vtable_t suunto_solution_device_vtable = {
 	NULL, /* write */
 	suunto_solution_device_dump, /* dump */
 	suunto_solution_device_foreach, /* foreach */
+	NULL, /* timesync */
 	suunto_solution_device_close /* close */
 };
 
diff --git a/src/suunto_vyper.c b/src/suunto_vyper.c
index ce44e05..33657dc 100644
--- a/src/suunto_vyper.c
+++ b/src/suunto_vyper.c
@@ -63,6 +63,7 @@ static const dc_device_vtable_t suunto_vyper_device_vtable = {
 	suunto_vyper_device_write, /* write */
 	suunto_vyper_device_dump, /* dump */
 	suunto_vyper_device_foreach, /* foreach */
+	NULL, /* timesync */
 	suunto_vyper_device_close /* close */
 };
 
diff --git a/src/suunto_vyper2.c b/src/suunto_vyper2.c
index 8ab521e..618ee4a 100644
--- a/src/suunto_vyper2.c
+++ b/src/suunto_vyper2.c
@@ -50,6 +50,7 @@ static const suunto_common2_device_vtable_t suunto_vyper2_device_vtable = {
 		suunto_common2_device_write, /* write */
 		suunto_common2_device_dump, /* dump */
 		suunto_common2_device_foreach, /* foreach */
+		NULL, /* timesync */
 		suunto_vyper2_device_close /* close */
 	},
 	suunto_vyper2_device_packet
diff --git a/src/suunto_vyper_parser.c b/src/suunto_vyper_parser.c
index 0ca8eaa..80f7d54 100644
--- a/src/suunto_vyper_parser.c
+++ b/src/suunto_vyper_parser.c
@@ -223,6 +223,7 @@ suunto_vyper_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datetime
 		datetime->hour   = p[3];
 		datetime->minute = p[4];
 		datetime->second = 0;
+		datetime->timezone = DC_TIMEZONE_NONE;
 	}
 
 	return DC_STATUS_SUCCESS;
diff --git a/src/usbhid.c b/src/usbhid.c
index 784b53c..c604cf4 100644
--- a/src/usbhid.c
+++ b/src/usbhid.c
@@ -25,14 +25,20 @@
 
 #include <stdlib.h>
 
-#if defined(HAVE_LIBUSB) && !defined(__APPLE__)
+#if defined(HAVE_HIDAPI)
+#define USE_HIDAPI
 #define USBHID
+#elif defined(HAVE_LIBUSB) && !defined(__APPLE__)
+#define USE_LIBUSB
+#define USBHID
+#endif
+
+#if defined(USE_LIBUSB)
 #ifdef _WIN32
 #define NOGDI
 #endif
 #include <libusb-1.0/libusb.h>
-#elif defined(HAVE_HIDAPI)
-#define USBHID
+#elif defined(USE_HIDAPI)
 #include <hidapi/hidapi.h>
 #endif
 
@@ -44,20 +50,20 @@ struct dc_usbhid_t {
 	/* Library context. */
 	dc_context_t *context;
 	/* Internal state. */
-#if defined(HAVE_LIBUSB) && !defined(__APPLE__)
+#if defined(USE_LIBUSB)
 	libusb_context *ctx;
 	libusb_device_handle *handle;
 	int interface;
 	unsigned char endpoint_in;
 	unsigned char endpoint_out;
 	unsigned int timeout;
-#elif defined(HAVE_HIDAPI)
+#elif defined(USE_HIDAPI)
 	hid_device *handle;
 	int timeout;
 #endif
 };
 
-#if defined(HAVE_LIBUSB) && !defined(__APPLE__)
+#if defined(USE_LIBUSB)
 static dc_status_t
 syserror(int errcode)
 {
@@ -94,6 +100,20 @@ usbhid_packet_read(dc_custom_io_t *io, void* data, size_t size, size_t *actual)
 	return dc_usbhid_read(usbhid, data, size, actual);
 }
 
+/*
+ * FIXME! The USB HID "report type" is a disaster, and there's confusion
+ * between libusb and HIDAPI. The Scubapro G2 seems to need an explicit
+ * report type of 0 for HIDAPI, but not for libusb.
+ *
+ * See commit d251b37 ("Add a zero report ID to the commands") for the
+ * Scubapro G2 - but that doesn't actually work with the BLE case, so
+ * I really suspect that we need to do something _here_ in the packet
+ * IO layer, and have the USBHID registration set the report type to
+ * use (ie an extra new argument to dc_usbhid_custom_io() to set the
+ * report type, or something).
+ *
+ * The Suunto EON Steel just uses 0x3f and does that in the caller.
+ */
 static dc_status_t
 usbhid_packet_write(dc_custom_io_t *io, const void* data, size_t size, size_t *actual)
 {
@@ -164,7 +184,7 @@ dc_usbhid_open (dc_usbhid_t **out, dc_context_t *context, unsigned int vid, unsi
 	// Library context.
 	usbhid->context = context;
 
-#if defined(HAVE_LIBUSB) && !defined(__APPLE__)
+#if defined(USE_LIBUSB)
 	struct libusb_device **devices = NULL;
 	struct libusb_config_descriptor *config = NULL;
 
@@ -296,7 +316,7 @@ dc_usbhid_open (dc_usbhid_t **out, dc_context_t *context, unsigned int vid, unsi
 	libusb_free_config_descriptor (config);
 	libusb_free_device_list (devices, 1);
 
-#elif defined(HAVE_HIDAPI)
+#elif defined(USE_HIDAPI)
 
 	// Initialize the hidapi library.
 	rc = hid_init();
@@ -321,7 +341,7 @@ dc_usbhid_open (dc_usbhid_t **out, dc_context_t *context, unsigned int vid, unsi
 
 	return DC_STATUS_SUCCESS;
 
-#if defined(HAVE_LIBUSB) && !defined(__APPLE__)
+#if defined(USE_LIBUSB)
 error_usb_close:
 	libusb_close (usbhid->handle);
 error_usb_free_config:
@@ -330,7 +350,7 @@ error_usb_free_list:
 	libusb_free_device_list (devices, 1);
 error_usb_exit:
 	libusb_exit (usbhid->ctx);
-#elif defined(HAVE_HIDAPI)
+#elif defined(USE_HIDAPI)
 error_hid_exit:
 	hid_exit ();
 #endif
@@ -351,11 +371,11 @@ dc_usbhid_close (dc_usbhid_t *usbhid)
 	if (usbhid == NULL)
 		return DC_STATUS_SUCCESS;
 
-#if defined(HAVE_LIBUSB) && !defined(__APPLE__)
+#if defined(USE_LIBUSB)
 	libusb_release_interface (usbhid->handle, usbhid->interface);
 	libusb_close (usbhid->handle);
 	libusb_exit (usbhid->ctx);
-#elif defined(HAVE_HIDAPI)
+#elif defined(USE_HIDAPI)
 	hid_close(usbhid->handle);
 	hid_exit();
 #endif
@@ -376,7 +396,7 @@ dc_usbhid_set_timeout (dc_usbhid_t *usbhid, int timeout)
 
 	INFO (usbhid->context, "Timeout: value=%i", timeout);
 
-#if defined(HAVE_LIBUSB) && !defined(__APPLE__)
+#if defined(USE_LIBUSB)
 	if (timeout < 0) {
 		usbhid->timeout = 0;
 	} else if (timeout == 0) {
@@ -384,7 +404,7 @@ dc_usbhid_set_timeout (dc_usbhid_t *usbhid, int timeout)
 	} else {
 		usbhid->timeout = timeout;
 	}
-#elif defined(HAVE_HIDAPI)
+#elif defined(USE_HIDAPI)
 	if (timeout < 0) {
 		usbhid->timeout = -1;
 	} else {
@@ -410,7 +430,7 @@ dc_usbhid_read (dc_usbhid_t *usbhid, void *data, size_t size, size_t *actual)
 		goto out_invalidargs;
 	}
 
-#if defined(HAVE_LIBUSB) && !defined(__APPLE__)
+#if defined(USE_LIBUSB)
 	int rc = libusb_interrupt_transfer (usbhid->handle, usbhid->endpoint_in, data, size, &nbytes, usbhid->timeout);
 	if (rc != LIBUSB_SUCCESS) {
 		ERROR (usbhid->context, "Usb read interrupt transfer failed (%s).",
@@ -418,11 +438,12 @@ dc_usbhid_read (dc_usbhid_t *usbhid, void *data, size_t size, size_t *actual)
 		status = syserror (rc);
 		goto out;
 	}
-#elif defined(HAVE_HIDAPI)
+#elif defined(USE_HIDAPI)
 	nbytes = hid_read_timeout(usbhid->handle, data, size, usbhid->timeout);
 	if (nbytes < 0) {
 		ERROR (usbhid->context, "Usb read interrupt transfer failed.");
 		status = DC_STATUS_IO;
+		nbytes = 0;
 		goto out;
 	}
 #endif
@@ -452,21 +473,46 @@ dc_usbhid_write (dc_usbhid_t *usbhid, const void *data, size_t size, size_t *act
 		goto out_invalidargs;
 	}
 
-#if defined(HAVE_LIBUSB) && !defined(__APPLE__)
-	int rc = libusb_interrupt_transfer (usbhid->handle, usbhid->endpoint_out, (void *) data, size, &nbytes, 0);
+	if (size == 0) {
+		goto out;
+	}
+
+#if defined(USE_LIBUSB)
+	const unsigned char *buffer = (const unsigned char *) data;
+	size_t length = size;
+
+	// Skip a report id of zero.
+	unsigned char report = buffer[0];
+	if (report == 0) {
+		buffer++;
+		length--;
+	}
+
+	int rc = libusb_interrupt_transfer (usbhid->handle, usbhid->endpoint_out, (void *) buffer, length, &nbytes, 0);
 	if (rc != LIBUSB_SUCCESS) {
 		ERROR (usbhid->context, "Usb write interrupt transfer failed (%s).",
 			libusb_error_name (rc));
 		status = syserror (rc);
 		goto out;
 	}
-#elif defined(HAVE_HIDAPI)
+
+	if (report == 0) {
+		nbytes++;
+	}
+#elif defined(USE_HIDAPI)
 	nbytes = hid_write(usbhid->handle, data, size);
 	if (nbytes < 0) {
 		ERROR (usbhid->context, "Usb write interrupt transfer failed.");
 		status = DC_STATUS_IO;
+		nbytes = 0;
 		goto out;
 	}
+
+#ifdef _WIN32
+	if (nbytes > size) {
+		nbytes = size;
+	}
+#endif
 #endif
 
 out:
diff --git a/src/uwatec_aladin.c b/src/uwatec_aladin.c
index d70369a..25c9208 100644
--- a/src/uwatec_aladin.c
+++ b/src/uwatec_aladin.c
@@ -62,6 +62,7 @@ static const dc_device_vtable_t uwatec_aladin_device_vtable = {
 	NULL, /* write */
 	uwatec_aladin_device_dump, /* dump */
 	uwatec_aladin_device_foreach, /* foreach */
+	NULL, /* timesync */
 	uwatec_aladin_device_close /* close */
 };
 
diff --git a/src/uwatec_memomouse.c b/src/uwatec_memomouse.c
index b23c6b2..2f93067 100644
--- a/src/uwatec_memomouse.c
+++ b/src/uwatec_memomouse.c
@@ -58,6 +58,7 @@ static const dc_device_vtable_t uwatec_memomouse_device_vtable = {
 	NULL, /* write */
 	uwatec_memomouse_device_dump, /* dump */
 	uwatec_memomouse_device_foreach, /* foreach */
+	NULL, /* timesync */
 	uwatec_memomouse_device_close /* close */
 };
 
diff --git a/src/uwatec_meridian.c b/src/uwatec_meridian.c
index d59b855..c32f3bc 100644
--- a/src/uwatec_meridian.c
+++ b/src/uwatec_meridian.c
@@ -56,6 +56,7 @@ static const dc_device_vtable_t uwatec_meridian_device_vtable = {
 	NULL, /* write */
 	uwatec_meridian_device_dump, /* dump */
 	uwatec_meridian_device_foreach, /* foreach */
+	NULL, /* timesync */
 	uwatec_meridian_device_close /* close */
 };
 
diff --git a/src/uwatec_smart.c b/src/uwatec_smart.c
index 425e76e..4fd2e2d 100644
--- a/src/uwatec_smart.c
+++ b/src/uwatec_smart.c
@@ -52,6 +52,7 @@ static const dc_device_vtable_t uwatec_smart_device_vtable = {
 	NULL, /* write */
 	uwatec_smart_device_dump, /* dump */
 	uwatec_smart_device_foreach, /* foreach */
+	NULL, /* timesync */
 	uwatec_smart_device_close /* close */
 };
 
diff --git a/src/uwatec_smart_parser.c b/src/uwatec_smart_parser.c
index 99bfa28..54bdee5 100644
--- a/src/uwatec_smart_parser.c
+++ b/src/uwatec_smart_parser.c
@@ -710,6 +710,8 @@ uwatec_smart_parser_get_datetime (dc_parser_t *abstract, dc_datetime_t *datetime
 
 		if (!dc_datetime_gmtime (datetime, ticks))
 			return DC_STATUS_DATAFORMAT;
+
+		datetime->timezone = utc_offset * 900;
 	} else {
 		// For devices without timezone support, the current timezone of
 		// the host system is used.
diff --git a/src/zeagle_n2ition3.c b/src/zeagle_n2ition3.c
index fed6ae2..3d2bb24 100644
--- a/src/zeagle_n2ition3.c
+++ b/src/zeagle_n2ition3.c
@@ -64,6 +64,7 @@ static const dc_device_vtable_t zeagle_n2ition3_device_vtable = {
 	NULL, /* write */
 	zeagle_n2ition3_device_dump, /* dump */
 	zeagle_n2ition3_device_foreach, /* foreach */
+	NULL, /* timesync */
 	zeagle_n2ition3_device_close /* close */
 };