Specifications
CRESTRON
Operations Guide - DOC. 8123 CNX RS-232/422/485 Expansion Card: CNXCOM-2 •• 3
1. Disconnect power from the CNMSX.
2. Use the Phillips tip screwdriver and remove two screws and blank
faceplate from the control system.
3. Align the CNXCOM-2 with the card guides in the open slot and slide
the expansion card into postion.
4. Firmly press both ends of the CNXCOM-2 faceplate to seat the
expansion card into the control system connector.
5. Tighten the thumb-nail screws to secure the CNXCOM-2 to the
control system.
6. Reapply power to the CNMSX.
Preparation for Use
Two distinct bidirectional serial ports are available from the CNXCOM-2 via two
non-standard DB9 connectors. Refer to a sample hookup diagram below and aside
from reapplying power to the control system last, complete the connections in any
order.
Sample Hookup Connections for CNXCOM-2
SERIAL
DEVICE
NOTE: The pinout of each 9-pin port is non-standard, therefore use of a straight-
through cable is not appropriate. The table following this note contains pinout
descriptions for RS-232 as well as RS-422. Conflicts with some equipment may
occur unless the controlled devices are properly wired. Certain devices have specific
voltage requirements. Therefore, do not use all nine pins in a given application.
Although the possibility is remote, improper wiring may result in damage to the
controlled device. Only the required pins for each communication type should be
connected.
Non-Standard COM Pinout (for RS-232 and RS-422 Communication)
PIN DIRECTION DESCRIPTION
1* To CNXCOM-2
(RXD-) RS-422 Receive Data (Idles low)
2 To CNXCOM-2
(RXD) RS-232 Received Data
3 From CNXCOM-2
(TXD) RS-232 Transmitted Data
4 From CNXCOM-2
(TXD+) RS-422 Transmit Data (Idles high)
5
RS-232 and RS-422 Signal Common
6 To CNXCOM-2
(RXD+) RS-422 Receive Data (Idles high)
7 From CNXCOM-2
(RTS) RS-232 Request to Send
8 To CNXCOM-2
(CTS) RS-232 Clear to Send
9 From CNXCOM-2
(TXD-) RS-422 Transmit Data (Idles low)
Where: * = RS-422 transmit and receive 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.