Automatic Vehicle Monitoring (AVM)

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Yarra Trams AVM - Unknown official name
Mpt1327 clone.png
Frequencies 517.875 MHz,507.225 MHz
Frequency Range 507.225 MHz - 517.875 MHz
Mode NFM
Modulation FFSK
ACF
Emission Designator
Bandwidth 7.5 kHz
Location Melbourne, Australia
Short Description Proprietary FFSK data network used for public transport telemetry.
I/Q Raw Recording Download file
Audio Sample

The Automatic Vehicle Monitoring (AVM) system was implemented on Melbourne's public Bus and Tram network in the 1980s. It is primarily used to track and control vehicles, as well as providing route information and location data. Since 2009 the system feeds the PIDs at tram stops and stations, as well as the TramTracker app for mobile devices.

Samples[edit]

Uplink

This sample below is the uplink channel. Note the rapid FFSKFast Frequency-Shift Keying data bursts from multiple mobile units:
AVM uplink.png


Voice Transmissions

Data is also transmitted at the end of each mobile voice transmission:

Tram driver communication:

Short conversation between driver and dispatch:

Additional Links[edit]