Keyscan CA250B - Test Points - Communication Terminals; Figure 56 - Control Board Communication Test Points; Table 17 - Communication Voltage Test Points

Keyscan Inc. – Technical Guide (PC109x - 04.15)
86
Test Points – Communication Terminals
The following table outlines the correct voltages for the test points on the communication terminal on the CA
or EC control board.
Table 17 – Communication Voltage Test Points
Communication Test Point
Voltage
Instructions/Notes
CA / EC Communication Terminal
RS-232 connected to ACU
Connect voltmeter COM to GND on ACU communication
terminal block or green on data cable.
GND
TD
(-) 9 VDC
TD is an ACU generated voltage
RD
(-) 10 VDC
RD is a PC generated voltage
DCD
DTR
n/a
CTS
n/a
Figure 56 – Control Board Communication Test Points
GND
RS-232 (COM4)
Control Board
(PC 109x)
TD
RD
DCD
DTR
CTS
IOCB (COM1)
RX
TX
KI-00194E-07-11