diff --git a/include/libdivecomputer/iostream.h b/include/libdivecomputer/iostream.h
index dab5daf..832680d 100644
--- a/include/libdivecomputer/iostream.h
+++ b/include/libdivecomputer/iostream.h
@@ -129,17 +129,6 @@ dc_iostream_set_timeout (dc_iostream_t *iostream, int timeout);
 dc_status_t
 dc_iostream_set_latency (dc_iostream_t *iostream, unsigned int value);
 
-/**
- * Set the state of the half duplex emulation.
- *
- * @param[in]  iostream  A valid I/O stream.
- * @param[in]  value     The half duplex state.
- * @returns #DC_STATUS_SUCCESS on success, or another #dc_status_t code
- * on failure.
- */
-dc_status_t
-dc_iostream_set_halfduplex (dc_iostream_t *iostream, unsigned int value);
-
 /**
  * Set the state of the break condition.
  *
diff --git a/src/bluetooth.c b/src/bluetooth.c
index 08347d5..772101f 100644
--- a/src/bluetooth.c
+++ b/src/bluetooth.c
@@ -99,7 +99,6 @@ static const dc_iostream_vtable_t dc_bluetooth_vtable = {
 	sizeof(dc_socket_t),
 	dc_socket_set_timeout, /* set_timeout */
 	dc_socket_set_latency, /* set_latency */
-	dc_socket_set_halfduplex, /* set_halfduplex */
 	dc_socket_set_break, /* set_break */
 	dc_socket_set_dtr, /* set_dtr */
 	dc_socket_set_rts, /* set_rts */
diff --git a/src/custom.c b/src/custom.c
index e96ba5f..519a39e 100644
--- a/src/custom.c
+++ b/src/custom.c
@@ -29,7 +29,6 @@
 
 static dc_status_t dc_custom_set_timeout (dc_iostream_t *abstract, int timeout);
 static dc_status_t dc_custom_set_latency (dc_iostream_t *abstract, unsigned int value);
-static dc_status_t dc_custom_set_halfduplex (dc_iostream_t *abstract, unsigned int value);
 static dc_status_t dc_custom_set_break (dc_iostream_t *abstract, unsigned int value);
 static dc_status_t dc_custom_set_dtr (dc_iostream_t *abstract, unsigned int value);
 static dc_status_t dc_custom_set_rts (dc_iostream_t *abstract, unsigned int value);
@@ -55,7 +54,6 @@ static const dc_iostream_vtable_t dc_custom_vtable = {
 	sizeof(dc_custom_t),
 	dc_custom_set_timeout, /* set_timeout */
 	dc_custom_set_latency, /* set_latency */
-	dc_custom_set_halfduplex, /* set_halfduplex */
 	dc_custom_set_break, /* set_break */
 	dc_custom_set_dtr, /* set_dtr */
 	dc_custom_set_rts, /* set_rts */
@@ -117,17 +115,6 @@ dc_custom_set_latency (dc_iostream_t *abstract, unsigned int value)
 	return custom->callbacks.set_latency (custom->userdata, value);
 }
 
-static dc_status_t
-dc_custom_set_halfduplex (dc_iostream_t *abstract, unsigned int value)
-{
-	dc_custom_t *custom = (dc_custom_t *) abstract;
-
-	if (custom->callbacks.set_halfduplex == NULL)
-		return DC_STATUS_UNSUPPORTED;
-
-	return custom->callbacks.set_halfduplex (custom->userdata, value);
-}
-
 static dc_status_t
 dc_custom_set_break (dc_iostream_t *abstract, unsigned int value)
 {
diff --git a/src/custom.h b/src/custom.h
index f062cd3..f1ab5da 100644
--- a/src/custom.h
+++ b/src/custom.h
@@ -33,7 +33,6 @@ extern "C" {
 typedef struct dc_custom_cbs_t {
 	dc_status_t (*set_timeout) (void *userdata, int timeout);
 	dc_status_t (*set_latency) (void *userdata, unsigned int value);
-	dc_status_t (*set_halfduplex) (void *userdata, unsigned int value);
 	dc_status_t (*set_break) (void *userdata, unsigned int value);
 	dc_status_t (*set_dtr) (void *userdata, unsigned int value);
 	dc_status_t (*set_rts) (void *userdata, unsigned int value);
diff --git a/src/iostream-private.h b/src/iostream-private.h
index 7f7be84..b9bd4f1 100644
--- a/src/iostream-private.h
+++ b/src/iostream-private.h
@@ -44,8 +44,6 @@ struct dc_iostream_vtable_t {
 
 	dc_status_t (*set_latency) (dc_iostream_t *iostream, unsigned int value);
 
-	dc_status_t (*set_halfduplex) (dc_iostream_t *iostream, unsigned int value);
-
 	dc_status_t (*set_break) (dc_iostream_t *iostream, unsigned int value);
 
 	dc_status_t (*set_dtr) (dc_iostream_t *iostream, unsigned int value);
diff --git a/src/iostream.c b/src/iostream.c
index e6c40ea..c1e3017 100644
--- a/src/iostream.c
+++ b/src/iostream.c
@@ -85,17 +85,6 @@ dc_iostream_set_latency (dc_iostream_t *iostream, unsigned int value)
 	return iostream->vtable->set_latency (iostream, value);
 }
 
-dc_status_t
-dc_iostream_set_halfduplex (dc_iostream_t *iostream, unsigned int value)
-{
-	if (iostream == NULL || iostream->vtable->set_halfduplex == NULL)
-		return DC_STATUS_UNSUPPORTED;
-
-	INFO (iostream->context, "Halfduplex: value=%i", value);
-
-	return iostream->vtable->set_halfduplex (iostream, value);
-}
-
 dc_status_t
 dc_iostream_set_break (dc_iostream_t *iostream, unsigned int value)
 {
diff --git a/src/irda.c b/src/irda.c
index 1ac754b..d1aecfb 100644
--- a/src/irda.c
+++ b/src/irda.c
@@ -92,7 +92,6 @@ static const dc_iostream_vtable_t dc_irda_vtable = {
 	sizeof(dc_socket_t),
 	dc_socket_set_timeout, /* set_timeout */
 	dc_socket_set_latency, /* set_latency */
-	dc_socket_set_halfduplex, /* set_halfduplex */
 	dc_socket_set_break, /* set_break */
 	dc_socket_set_dtr, /* set_dtr */
 	dc_socket_set_rts, /* set_rts */
diff --git a/src/libdivecomputer.symbols b/src/libdivecomputer.symbols
index daed9ef..a0c3724 100644
--- a/src/libdivecomputer.symbols
+++ b/src/libdivecomputer.symbols
@@ -34,7 +34,6 @@ dc_descriptor_get_model
 dc_descriptor_get_transport
 
 dc_iostream_set_timeout
-dc_iostream_set_halfduplex
 dc_iostream_set_latency
 dc_iostream_set_break
 dc_iostream_set_dtr
diff --git a/src/serial_posix.c b/src/serial_posix.c
index 8922c3a..352655b 100644
--- a/src/serial_posix.c
+++ b/src/serial_posix.c
@@ -68,7 +68,6 @@ static dc_status_t dc_serial_iterator_free (dc_iterator_t *iterator);
 
 static dc_status_t dc_serial_set_timeout (dc_iostream_t *iostream, int timeout);
 static dc_status_t dc_serial_set_latency (dc_iostream_t *iostream, unsigned int value);
-static dc_status_t dc_serial_set_halfduplex (dc_iostream_t *iostream, unsigned int value);
 static dc_status_t dc_serial_set_break (dc_iostream_t *iostream, unsigned int value);
 static dc_status_t dc_serial_set_dtr (dc_iostream_t *iostream, unsigned int value);
 static dc_status_t dc_serial_set_rts (dc_iostream_t *iostream, unsigned int value);
@@ -106,10 +105,6 @@ typedef struct dc_serial_t {
 	 * serial port is closed.
 	 */
 	struct termios tty;
-	/* Half-duplex settings */
-	int halfduplex;
-	unsigned int baudrate;
-	unsigned int nbits;
 } dc_serial_t;
 
 static const dc_iterator_vtable_t dc_serial_iterator_vtable = {
@@ -122,7 +117,6 @@ static const dc_iostream_vtable_t dc_serial_vtable = {
 	sizeof(dc_serial_t),
 	dc_serial_set_timeout, /* set_timeout */
 	dc_serial_set_latency, /* set_latency */
-	dc_serial_set_halfduplex, /* set_halfduplex */
 	dc_serial_set_break, /* set_break */
 	dc_serial_set_dtr, /* set_dtr */
 	dc_serial_set_rts, /* set_rts */
@@ -286,11 +280,6 @@ dc_serial_open (dc_iostream_t **out, dc_context_t *context, const char *name)
 	// Default to blocking reads.
 	device->timeout = -1;
 
-	// Default to full-duplex.
-	device->halfduplex = 0;
-	device->baudrate = 0;
-	device->nbits = 0;
-
 	// Create a high resolution timer.
 	status = dc_timer_new (&device->timer);
 	if (status != DC_STATUS_SUCCESS) {
@@ -619,9 +608,6 @@ dc_serial_configure (dc_iostream_t *abstract, unsigned int baudrate, unsigned in
 #endif
 	}
 
-	device->baudrate = baudrate;
-	device->nbits = 1 + databits + stopbits + (parity ? 1 : 0);
-
 	return DC_STATUS_SUCCESS;
 }
 
@@ -635,16 +621,6 @@ dc_serial_set_timeout (dc_iostream_t *abstract, int timeout)
 	return DC_STATUS_SUCCESS;
 }
 
-static dc_status_t
-dc_serial_set_halfduplex (dc_iostream_t *abstract, unsigned int value)
-{
-	dc_serial_t *device = (dc_serial_t *) abstract;
-
-	device->halfduplex = value;
-
-	return DC_STATUS_SUCCESS;
-}
-
 static dc_status_t
 dc_serial_set_latency (dc_iostream_t *abstract, unsigned int milliseconds)
 {
@@ -781,17 +757,6 @@ dc_serial_write (dc_iostream_t *abstract, const void *data, size_t size, size_t
 	dc_serial_t *device = (dc_serial_t *) abstract;
 	size_t nbytes = 0;
 
-	struct timeval tve, tvb;
-	if (device->halfduplex) {
-		// Get the current time.
-		if (gettimeofday (&tvb, NULL) != 0) {
-			int errcode = errno;
-			SYSERROR (abstract->context, errcode);
-			status = syserror (errcode);
-			goto out;
-		}
-	}
-
 	while (nbytes < size) {
 		fd_set fds;
 		FD_ZERO (&fds);
@@ -839,35 +804,6 @@ dc_serial_write (dc_iostream_t *abstract, const void *data, size_t size, size_t
 		}
 	}
 
-	if (device->halfduplex) {
-		// Get the current time.
-		if (gettimeofday (&tve, NULL) != 0) {
-			int errcode = errno;
-			SYSERROR (abstract->context, errcode);
-			status = syserror (errcode);
-			goto out;
-		}
-
-		// Calculate the elapsed time (microseconds).
-		struct timeval tvt;
-		timersub (&tve, &tvb, &tvt);
-		unsigned long elapsed = tvt.tv_sec * 1000000 + tvt.tv_usec;
-
-		// Calculate the expected duration (microseconds). A 2 millisecond fudge
-		// factor is added because it improves the success rate significantly.
-		unsigned long expected = 1000000.0 * device->nbits / device->baudrate * size + 0.5 + 2000;
-
-		// Wait for the remaining time.
-		if (elapsed < expected) {
-			unsigned long remaining = expected - elapsed;
-
-			// The remaining time is rounded up to the nearest millisecond to
-			// match the Windows implementation. The higher resolution is
-			// pointless anyway, since we already added a fudge factor above.
-			dc_serial_sleep (abstract, (remaining + 999) / 1000);
-		}
-	}
-
 out:
 	if (actual)
 		*actual = nbytes;
diff --git a/src/serial_win32.c b/src/serial_win32.c
index c9b31e9..b0c6050 100644
--- a/src/serial_win32.c
+++ b/src/serial_win32.c
@@ -37,7 +37,6 @@ static dc_status_t dc_serial_iterator_free (dc_iterator_t *iterator);
 
 static dc_status_t dc_serial_set_timeout (dc_iostream_t *iostream, int timeout);
 static dc_status_t dc_serial_set_latency (dc_iostream_t *iostream, unsigned int value);
-static dc_status_t dc_serial_set_halfduplex (dc_iostream_t *iostream, unsigned int value);
 static dc_status_t dc_serial_set_break (dc_iostream_t *iostream, unsigned int value);
 static dc_status_t dc_serial_set_dtr (dc_iostream_t *iostream, unsigned int value);
 static dc_status_t dc_serial_set_rts (dc_iostream_t *iostream, unsigned int value);
@@ -76,10 +75,6 @@ typedef struct dc_serial_t {
 	 */
 	DCB dcb;
 	COMMTIMEOUTS timeouts;
-	/* Half-duplex settings */
-	int halfduplex;
-	unsigned int baudrate;
-	unsigned int nbits;
 } dc_serial_t;
 
 static const dc_iterator_vtable_t dc_serial_iterator_vtable = {
@@ -92,7 +87,6 @@ static const dc_iostream_vtable_t dc_serial_vtable = {
 	sizeof(dc_serial_t),
 	dc_serial_set_timeout, /* set_timeout */
 	dc_serial_set_latency, /* set_latency */
-	dc_serial_set_halfduplex, /* set_halfduplex */
 	dc_serial_set_break, /* set_break */
 	dc_serial_set_dtr, /* set_dtr */
 	dc_serial_set_rts, /* set_rts */
@@ -288,11 +282,6 @@ dc_serial_open (dc_iostream_t **out, dc_context_t *context, const char *name)
 		return DC_STATUS_NOMEMORY;
 	}
 
-	// Default to full-duplex.
-	device->halfduplex = 0;
-	device->baudrate = 0;
-	device->nbits = 0;
-
 	// Open the device.
 	device->hFile = CreateFileA (devname,
 			GENERIC_READ | GENERIC_WRITE, 0,
@@ -457,9 +446,6 @@ dc_serial_configure (dc_iostream_t *abstract, unsigned int baudrate, unsigned in
 		return syserror (errcode);
 	}
 
-	device->baudrate = baudrate;
-	device->nbits = 1 + databits + stopbits + (parity ? 1 : 0);
-
 	return DC_STATUS_SUCCESS;
 }
 
@@ -510,16 +496,6 @@ dc_serial_set_timeout (dc_iostream_t *abstract, int timeout)
 	return DC_STATUS_SUCCESS;
 }
 
-static dc_status_t
-dc_serial_set_halfduplex (dc_iostream_t *abstract, unsigned int value)
-{
-	dc_serial_t *device = (dc_serial_t *) abstract;
-
-	device->halfduplex = value;
-
-	return DC_STATUS_SUCCESS;
-}
-
 static dc_status_t
 dc_serial_set_latency (dc_iostream_t *abstract, unsigned int value)
 {
@@ -558,18 +534,6 @@ dc_serial_write (dc_iostream_t *abstract, const void *data, size_t size, size_t
 	dc_serial_t *device = (dc_serial_t *) abstract;
 	DWORD dwWritten = 0;
 
-	LARGE_INTEGER begin, end, freq;
-	if (device->halfduplex) {
-		// Get the current time.
-		if (!QueryPerformanceFrequency(&freq) ||
-			!QueryPerformanceCounter(&begin)) {
-			DWORD errcode = GetLastError ();
-			SYSERROR (abstract->context, errcode);
-			status = syserror (errcode);
-			goto out;
-		}
-	}
-
 	if (!WriteFile (device->hFile, data, size, &dwWritten, NULL)) {
 		DWORD errcode = GetLastError ();
 		SYSERROR (abstract->context, errcode);
@@ -577,33 +541,6 @@ dc_serial_write (dc_iostream_t *abstract, const void *data, size_t size, size_t
 		goto out;
 	}
 
-	if (device->halfduplex) {
-		// Get the current time.
-		if (!QueryPerformanceCounter(&end))  {
-			DWORD errcode = GetLastError ();
-			SYSERROR (abstract->context, errcode);
-			status = syserror (errcode);
-			goto out;
-		}
-
-		// Calculate the elapsed time (microseconds).
-		unsigned long elapsed = 1000000.0 * (end.QuadPart - begin.QuadPart) / freq.QuadPart + 0.5;
-
-		// Calculate the expected duration (microseconds). A 2 millisecond fudge
-		// factor is added because it improves the success rate significantly.
-		unsigned long expected = 1000000.0 * device->nbits / device->baudrate * size + 0.5 + 2000;
-
-		// Wait for the remaining time.
-		if (elapsed < expected) {
-			unsigned long remaining = expected - elapsed;
-
-			// The remaining time is rounded up to the nearest millisecond
-			// because the Windows Sleep() function doesn't have a higher
-			// resolution.
-			dc_serial_sleep (abstract, (remaining + 999) / 1000);
-		}
-	}
-
 	if (dwWritten != size) {
 		status = DC_STATUS_TIMEOUT;
 	}
diff --git a/src/socket.c b/src/socket.c
index 5ce392f..1842a75 100644
--- a/src/socket.c
+++ b/src/socket.c
@@ -169,12 +169,6 @@ dc_socket_set_latency (dc_iostream_t *iostream, unsigned int value)
 	return DC_STATUS_SUCCESS;
 }
 
-dc_status_t
-dc_socket_set_halfduplex (dc_iostream_t *iostream, unsigned int value)
-{
-	return DC_STATUS_SUCCESS;
-}
-
 dc_status_t
 dc_socket_set_break (dc_iostream_t *iostream, unsigned int value)
 {
diff --git a/src/socket.h b/src/socket.h
index d612603..626003c 100644
--- a/src/socket.h
+++ b/src/socket.h
@@ -107,9 +107,6 @@ dc_socket_set_timeout (dc_iostream_t *iostream, int timeout);
 dc_status_t
 dc_socket_set_latency (dc_iostream_t *iostream, unsigned int value);
 
-dc_status_t
-dc_socket_set_halfduplex (dc_iostream_t *iostream, unsigned int value);
-
 dc_status_t
 dc_socket_set_break (dc_iostream_t *iostream, unsigned int value);
 
diff --git a/src/usbhid.c b/src/usbhid.c
index b2dfa16..244e175 100644
--- a/src/usbhid.c
+++ b/src/usbhid.c
@@ -119,7 +119,6 @@ static const dc_iostream_vtable_t dc_usbhid_vtable = {
 	sizeof(dc_usbhid_t),
 	dc_usbhid_set_timeout, /* set_timeout */
 	NULL, /* set_latency */
-	NULL, /* set_halfduplex */
 	NULL, /* set_break */
 	NULL, /* set_dtr */
 	NULL, /* set_rts */