Specifications

Engineering Standard –NSW
Signalling SMS 02
Cerberus Level Crossing Monitor Equipment
March 2005 Version 1.2 © Australian Rail Track Corporation Page 49 of 118
This document is uncontrolled when printed.
3.8.3 DPX-224 Modem
For the Dataplex DPX-224 the following commands the following
modem initialisation string is required.
AT &F &C1 &D0 S0=2 Q1 E0 B0 X0 &W
The DPX-224 modem requires the serial port A to be set at 1200bps or
2400bps.
3.8.4 Maestro Executive 144FM Modem
For the Maestro Executive 144FM the following commands the
following modem initialisation string is required.
AT &F &C1 &D2 S0=2 Q1 E0 &K0 %C0 \N0 T L1 &W0 Serial port A is
set for 9600bps to provide consistency.
This modem should not be used with normal level crossing monitor
installations as it normally operates from 240V AC. This modem uses a
240V AC - 9 VDC plugpack to power the modem. This modem may be
able to be used with a level crossing monitor installation by operating
the modem off the sensor supply or off the level crossing battery supply
using a regulator unit.
3.8.5 Modem Replacement
If the modem answers and you are unable to communicate with the
monitor then turn the modem off, wait 5 seconds and then turn it back
on. The modem is reconfigured by ensuring the modem is plugged into
serial port A and resetting the level crossing monitor (resetting the
monitor by turning it off and back on OR by pushing the reset
pushbutton on the I/O card).
If turning the modem off then on and re-configuring it does not correct
the fault then replace the modem.
Turn the power off to the modem via the switch on the back of the
modem or by disconnecting the connector. Disconnect the power
leads, unplug the telephone line and the serial cable. Re-connect the
new modem taking special care with the polarity of the power leads
positive and negative. The positive lead has a red strip running down
the length of the wire.
Turn the new modem on via the switch on the back of it or by inserting
the connector. Re-configure the modem by resetting the Level Crossing
monitor (red push button in the middle of the I/O Board). Watch the
modem. The TX data LED should flash when it is reconfigured.
The Dataplex DPX-223 modems are no longer available new from
Dataplex. The DPX-213 (10-20V DC version) should be used as a
replacement.