Model 8P-MAS
Page 6
INSTALLATION
Master and Switched Ports
Connection to the Switched A-H ports is made using 25 pin D Subminiature connectors on the rear of
the unit. The following leads are supported for Asynchronous communications:
Pin # Designation
2
Transmit Data
3
Receive Data
4
Request to Send
5
Clear to Send
6
Data Set Ready
7
Signal Ground
8
Data Carrier Detect
20
Data Terminal Ready
The eight switched ports A-H are wired DCE (output
data on pin 3,RD). The Master port is wired for as DTE.
To directly connect a terminal device to the Master
Port, a Null cable is required. Refer to Figure 4 below.
RTS / DTR Selection
Jumpers JP1 through JP8 allows selection of RTS or DTR as the control lead used in the Lead Control
mode. To access these jumpers, disconnect the power source and remove the top cover of the 8P-
CAS by loosening the two screws on the underside of the unit. The jumpers are located as shown
below on Figure 3.
Figure 3
Component Location
Typical
Port A-H
RTS
Mon.
Switch
Control
Code
Mon.
Electronic
4 Way
Switch
2 TD
3 RD
4 RTS
5 CTS
6 DSR
8 DCD
DTR
20
7 SG
2 TD
3 RD
4 RTS
5 CTS
6 DSR
8 DCD
DTR
20
7 SG
Master
Port
Figure 2
System Diagram
DTR
RTS
