Installation guide

145
Options range=range
The port or range of ports to which this command applies.
mode={232|485}
Selects the electrical interface of the serial port. The selected value
determines whether the "wires" and "termination" options are
meaningful.
232
The serial port uses electrical interface EIA-232. This
interface uses independent wires to transmit and receive data,
which allows data to be sent and received between devices
simultaneously.
485
The serial port uses electrical interface EIA-485. This mode
can also be used for EIA-422 connections. This interface
uses two wires to both transmit and receive data. This
interface also allows for multiple transmitters and receivers
to be easily connected together.
The "wires" and "termination" command options
specifically apply to serial ports in EIA-485 mode.
The default is "232."
wires={two|four}
Applies when the serial port is running in EIA-485 mode only.
Selects the number of differential wires used for communication and
implicitly determines the duplex of the connection.
two
The serial port operates in two-wire mode. This mode is a
half-duplex connection with shared transmit and receive
wires.
four
The serial port operates in four-wire mode. This mode is a
full-duplex connection with independent transmit and
receive pairs.
The default is "four."