Specifications

Cascade Modem Manual
Copyright © 2007 Diamond Traffic Products, Inc
Page 11
2.8. RS232 Serial Interface
The modem uses a standard DB9 style RS232 interface connector. This supports a full RS-232C/V.24 serial
interface.
The modem is controlled by sending it serial commands over the TXD (transmit) and can be monitored by serial
status messages returned on RXD (receive).
RS232 DB9 Pinout:
Pin #
In/Out
Name
Function
1
Out
DCD
Data Carrier Detect
2
Out
RXD
Received Data
3
In
TXD
Transmit Data
4
In
DTR
Data Terminal Ready
5
-
GND
Ground
6
Out
DSR
Data Set Ready
7
In
RTS
Ready To Send
8
Out
CTS
Clear To Send
9
In/Out
RNG
Ring Output or Power
Input
-
Shield
Ground or Power Input
2.9. Ring Detect Relay
The Cascade Modem can be purchased with an optional 1 Amp Relay Contact Closure. This circuit activates for
approx. 2 seconds each time the phone rings, and provides a way for the user to connect other devices or systems
to the modem which need a signal indicating a Ring. The most common usage of this feature is to perform an
automatic power on of Peek 241 counters.
Connector
Pin #
Wire Color
Function
Green
Common Connection
Blue
Normally Open
Tan
Normally Closed
Black
Ground
NOTE: Unless absolutely necessary, do not connect the Ground pin to anything. It is preferable to keep the ground
isolated in this case.