Specifications

RailCorp Engineering Manual — Signals — Equipment Manual

Cerberus Level Crossing Monitor Field Equipment Manual TMG E1261

Issued August 2012 UNCONTROLLED WHEN PRINTED Version 2.1

A number of level crossing monitors and modems have been damaged by surges on the

phone line which could have been prevented with a suitable surge protection device on

the phone line.

Generally the configuration of the modem is set for the following features to operate

correctly with the level crossing monitor.

Recall the factory default settings.

Set the modem to autoanswer after 2 rings

Set carrier detect control to follow phone line data carrier, this is required to operate the

level crossing monitor correctly

Enable hanging up the modem using the DTR control line.

Disable response codes 7 & 8 so that the modem will not abort call if line is busy. (this

may be required with railway exchange/PABXs, put it in anyhow)

Disable flow control

Disable MNP error correction and data compression

Disable the echoing of commands back to the local terminal

Quiet mode, No echo

Save this new configuration to non volatile memory so that this configuration is

remembered even with the modem switched off.

Details of the cable that connects the modem to either a Personal Computer or to the

Level Crossing Monitor are given in drawing M08-863 Modem Cable.

Note that if the modem initialisation string is set correctly in the Level Crossing monitor

then the level crossing monitor, at start up automatically reconfigures the modem

connected to the A serial port.

Note Make sure the number ‘0’ is a zero and not a letter ‘O’ in the modem configuration

string.

2.8.1 DPX-223 Modem

For the Dataplex DPX-223 the following commands the following modem initialisation

string is required.

AT &F &C1 &D2 S0=2 Q1 E0 &E0 &K0 X2 &W

Serial port A is set for 9600bps to provide consistency.

2.8.2 DPX-213 Modem

For the Dataplex DPX-213 the following commands the following modem initialisation

string is required.

AT &F &C1 &D2 S0=2 Q1 E0 &E0 &K0 X2 &W

The DPX-213 modem requires the serial port A to be set at 9600bps.

It will not

operate at 19200bps.