Crestron electronic RS-232/42 - Manual (Page 8)

Ethernet RS-232/422 COM Module Crestron CEN-COM
COM A / B
These two 9-pin connectors (DB9) connect to serial equipment. These bidirectional
serial ports are used for RS-232, RS-422, or RS-485 communication.
NOTE: The pinout of each 9-pin port is non-standard (refer to table after this note);
it contains RS-422 pins in addition to RS-232. This may result in a conflict with
some equipment and therefore do not use all nine pins. Only the required pins for
each communication type should be connected.
NOTE: To support RS-485, tie pin 1 (RXD-) to pin 9 (TXD-) and pin 4 (TXD+) to
pin 6 (RXD+) in the cable, as shown below.
CEN-COM Pinout (COM A / B)
PIN DIRECTION DESCRIPTION
1* To CEN-COM (RXD-) RS-422 Receive Data (Idles low)
2 To CEN-COM (RXD) RS-232 Receive Data
3 From CEN-COM (TXD) RS-232 Transmit Data
4 From CEN-COM (TXD+) RS-422 Transmit Data (Idles high)
5 RS-232 and RS-422 Signal Common
6 To CEN-COM (RXD+) RS-422 Receive Data (Idles high)
7 From CEN-COM (RTS) RS-232 Request to Send
8 To CEN-COM (CTS) RS-232 Clear to Send
9 From CEN-COM (TXD-) RS-422 Transmit Data (Idles low)
* RS-422/RS-485 are balanced signals requiring two lines plus a ground in each direction. RXD+ and
TXD+ should idle high (going low at start of data transmission). RXD- and TXD- should idle low(going
high at start of data transmission). If necessary, RXD+/RXD- and TXD+/TXD- may be swapped to
maintain correct signal levels.
Ethernet (on front panel)
This unmarked RJ45 modular connector provides Ethernet connection, thereby
making the unit IP addressable and compatible with 10BASE-T Ethernet systems.
The Ethernet port is the standard 10BASE-T pinout. Refer to the pinout table after
this paragraph.
4 • Ethernet RS-232/422 COM Module: CEN-COM Operations Guide - DOC. 5719