Keyscan Technical Guide (PC109x - 04.12)
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Installation Notes
Typically, the black wire of the RS-232 cable from the PC, which is the receive data input of the PC, is
connected to the serial port TD pin of most Keyscan products.
Typically, the red wire of the RS-232 cable, which is the transmit data output of the PC, is connected to
the RD pin of most Keyscan products.
Exceptions - NETCOMs
When connecting any of the following NETCOM devices – NETCOM2, NETCOM2H, NETCOM2WH, NETCOM6,
NETCOM6H, or NETCOM6WH – the black and red wires are reversed as shown on the NETCOM wiring
diagrams. Please observe the following connections:
The black wire of the RS-232 cable connects to the RD terminal.
The red wire of the RS-232 cable connects to the TD terminal.
If during communication troubleshooting you remove the terminal block if it is wired for a NETCOM, as
listed above, and attach it to the communication port of the control board, or vise versa, system
communication will fail.