User manual

Section 3 - Installation and Initial Setup Vlinx VESR4x4 Serial Server
Page 20 of 70 Manual Documentation Number: VESR4x4-0712m
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Signals are single-ended and referenced to Signal Ground. Default
communications parameters are 9600, 8, N, 1 (9600 baud, 8 data bits, no
parity, 1 stop bit), and no flow control.
Note: The VESR4x4 is configured as a DTE. If it is connected to a computer or other DTE device, use a
null modem (cross-over) cable. If the serial device is configured as a DCE, use a straight-through
cable.
RS-422
RS-422 connections support two signal pairs: TDA (-), TDB (+), RDA (-), RDB
(+) and GND. The data lines are differential pairs (A & B) in which the B line is
positive relative to the A line in the idle (mark) state. In RS-422, the
transmitter is always enabled. Signal Ground provides a common mode
reference for the signal lines.
RS-485
RS-485 connections support 2-wire or 4-wire operation. In RS-485 mode, the
transmitter is only enabled when the serial server is transmitting data on the
line. This allows other devices to share the bus.
When configured for 4-wire operation the connection supports two signal
pairs: TDA (-), TDB (+), RDA (-), RDB (+) and GND. This makes full-duplex
operation possible. The data lines are differential pairs (A & B) in which the B
line is positive relative to the A line in the idle (mark) state. Signal Ground
provides a common mode reference for the signal lines.
When configured for 2-wire operation the connection supports one signal
pair: Data A (-) and Data B (+). These lines transmit and receive signals using
half-duplex operation. The data lines are differential with the Data B line
positive relative to Data A in the idle (mark) state. Signal Ground provides a
common mode reference for the signal lines.