-Specifies the port used to connect to the host. The port can either be given as
-a number or as a service name. Please note that the I<Service> argument must be
-a string, even if ports are given in their numerical form. Defaults to "502".
+for Modbus/TCP, specifies the port used to connect to the host. The port can
+either be given as a number or as a service name. Please note that the
+I<Service> argument must be a string, even if ports are given in their numerical
+form. Defaults to "502".
+
+=item B<Device> I<Devicenode>
+
+For Modbus/RTU, specifies the path to the serial device being used.
+
+=item B<Baudrate> I<Baudrate>
+
+For Modbus/RTU, specifies the baud rate of the serial device.
+Note, connections currently support only 8/N/1.