diff --git a/doc/Makefile.am b/doc/Makefile.am
index 82ef6ec..778d9e1 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -3,10 +3,10 @@ MAN3 = \
         modbus_connect.3 \
         modbus_flush.3 \
         modbus_free.3 \
+        modbus_get_byte_timeout.3 \
         modbus_get_header_length.3 \
         modbus_get_socket.3 \
         modbus_get_response_timeout.3 \
-        modbus_get_byte_timeout.3 \
         modbus_new_rtu.3 \
         modbus_new_tcp_pi.3 \
         modbus_new_tcp.3 \
@@ -16,13 +16,15 @@ MAN3 = \
         modbus_read_registers.3 \
         modbus_receive.3 \
         modbus_receive_confirmation.3 \
+        modbus_rtu_get_serial_mode.3 \
+        modbus_rtu_set_serial_mode.3 \
         modbus_send_raw_request.3 \
+        modbus_set_byte_timeout.3 \
         modbus_set_debug.3 \
         modbus_set_error_recovery.3 \
         modbus_set_slave.3 \
         modbus_set_socket.3 \
         modbus_set_response_timeout.3 \
-        modbus_set_byte_timeout.3 \
         modbus_strerror.3 \
         modbus_write_bits.3 \
         modbus_write_bit.3 \
diff --git a/doc/libmodbus.txt b/doc/libmodbus.txt
index 1375f38..633deea 100644
--- a/doc/libmodbus.txt
+++ b/doc/libmodbus.txt
@@ -66,6 +66,12 @@ is used to filter messages.
 Create a Modbus RTU context::
     linkmb:modbus_new_rtu[3]
 
+
+Set the serial mode::
+    linkmb:modbus_rtu_get_serial_mode[3]
+    linkmb:modbus_rtu_set_serial_mode[3]
+
+
 TCP (IPv4) Context
 ^^^^^^^^^^^^^^^^^^
 The TCP backend implements a Modbus variant used for communications over
diff --git a/doc/modbus_rtu_get_serial_mode.txt b/doc/modbus_rtu_get_serial_mode.txt
new file mode 100644
index 0000000..58162e4
--- /dev/null
+++ b/doc/modbus_rtu_get_serial_mode.txt
@@ -0,0 +1,52 @@
+modbus_rtu_get_serial_mode(3)
+=============================
+
+
+NAME
+----
+modbus_rtu_get_serial_mode - get the current serial mode
+
+
+SYNOPSIS
+--------
+*int modbus_rtu_get_serial_mode(*modbus_t 'ctx');*
+
+
+DESCRIPTION
+-----------
+The _modbus_rtu_get_serial_mode()_ function shall return the serial mode
+currently used by the libmodbus context:
+
+*MODBUS_RTU_RS232*:: the serial line is set for RS232 communication. RS-232
+ (Recommended Standard 232) is the traditional name for a series of standards
+ for serial binary single-ended data and control signals connecting between a
+ DTE (Data Terminal Equipment) and a DCE (Data Circuit-terminating
+ Equipment). It is commonly used in computer serial ports
+
+*MODBUS_RTU_RS485*:: the serial line is set for RS485 communication. EIA-485,
+ also known as TIA/EIA-485 or RS-485, is a standard defining the electrical
+ characteristics of drivers and receivers for use in balanced digital multipoint
+ systems. This standard is widely used for communications in industrial
+ automation because it can be used effectively over long distances and in
+ electrically noisy environments.
+
+This function is only available on recent Linux kernels.
+
+
+RETURN VALUE
+------------
+The _modbus_rtu_get_serial_mode()_ function shall return 'MODBUS_RTU_RS232' or
+'MODBUS_RTU_RS485' if successful. Otherwise it shall return -1 and set errno to
+one of the values defined below.
+
+
+ERRORS
+------
+*EINVAL*::
+The current libmodbus backend is not RTU.
+
+
+AUTHORS
+-------
+The libmodbus documentation was written by Stéphane Raimbault
+<stephane.raimbault@gmail.com>
diff --git a/doc/modbus_rtu_set_serial_mode.txt b/doc/modbus_rtu_set_serial_mode.txt
new file mode 100644
index 0000000..077982a
--- /dev/null
+++ b/doc/modbus_rtu_set_serial_mode.txt
@@ -0,0 +1,53 @@
+modbus_rtu_set_serial_mode(3)
+=============================
+
+
+NAME
+----
+modbus_rtu_set_serial_mode - set the serial mode
+
+
+SYNOPSIS
+--------
+*int modbus_rtu_set_serial_mode(*modbus_t 'ctx');*
+
+
+DESCRIPTION
+-----------
+The _modbus_rtu_set_serial_mode()_ function shall set the selected serial
+mode:
+
+*MODBUS_RTU_RS232*:: the serial line is set for RS232 communication. RS-232
+ (Recommended Standard 232) is the traditional name for a series of standards
+ for serial binary single-ended data and control signals connecting between a
+ DTE (Data Terminal Equipment) and a DCE (Data Circuit-terminating
+ Equipment). It is commonly used in computer serial ports
+
+*MODBUS_RTU_RS485*:: the serial line is set for RS485 communication. EIA-485,
+ also known as TIA/EIA-485 or RS-485, is a standard defining the electrical
+ characteristics of drivers and receivers for use in balanced digital multipoint
+ systems. This standard is widely used for communications in industrial
+ automation because it can be used effectively over long distances and in
+ electrically noisy environments.
+
+This function is only available on recent Linux kernels.
+
+
+RETURN VALUE
+------------
+The _modbus_set_serial_mode()_ function shall return 0 if successful. Otherwise
+it shall return -1 and set errno to one of the values defined below.
+
+
+ERRORS
+------
+*EINVAL*::
+The current libmodbus backend is not RTU.
+
+If the call to ioctl() fails, the error code of ioctl will be returned.
+
+
+AUTHORS
+-------
+The libmodbus documentation was written by Stéphane Raimbault
+<stephane.raimbault@gmail.com>