Section 3 - Installation and Initial Setup
Vlinx VESR4x4 Serial Server
Page 20 of 70
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RS-232
Models using DB9M connectors
support seven RS-232 signal lines (TD, RD,
DTR, DSR, RTS, CTS, DCD) plus Signal Ground.
Models using five position pluggable terminal blocks
support four signal
lines (TD, RD, RTS, CTS) plus Signal Ground.
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.
