Specifications

Engineering Standard –NSW
Signalling SMS 02
Cerberus Level Crossing Monitor Equipment
March 2005 Version 1.2 © Australian Rail Track Corporation Page 14 of 118
This document is uncontrolled when printed.
line is engaged or faulty the modem is hung-up and the monitor will
try again. The number of retries and the timing of retries is in
compliance with the AUSTEL regulations for operating modems.
If present in the level crossing location when a monitor status
change is being reported by the level crossing monitor to a Control
Centre you would see and hear the following sequence:
 Hear dial-tone and red OH indication on the modem turn on as
the monitor picks up the phone.
 Hear tone or pulse dialling from the modem.
 Hear ring tone from the modem.
 Hear answer tones from the modem as the Control Centre
answers its phone line.
 See the green CD indication on the modem turn on and the
modem go quiet.
 See some seconds later the yellow TD and RD indications on
the modem flash as the message is sent and a return
acknowledgment is received.
 See the green CD and red OH indications turn off as the monitor
hangs-up the phone.
2.4.2 Maintenance disable of Status Reporting
The maintainer may temporarily disable Status Reporting by holding
the Fault Reset button pressed for 5 seconds. The LOGIC led will
flash once per second to indicate that the monitor has had its
reporting of status changes disabled temporarily. When in this mode
the monitor will not report changes of status to the Control Centre.
This mode is cancelled by a momentary push of the Fault Reset
button or at pre-programmed interval after activation. Normally this
time-out is set at 45 minutes. All Fault and Warning conditions must
be cleared before cancelling this mode otherwise they will be
reported to the Control Centre.
Note that the maintenance disable feature is a part of the
expression file and can be disabled if required by modifying the
expression file.
2.4.3 Codes reported to Control Centre
The level crossing monitor will report a Fault or Warning and one of
the following codes when it detects a change in the status of the
crossing. These directly relate to the monitor front panel indications
discussed previously. But also include some additional information by
identifying some indications that are grouped on the front panel.