BAS Rail & Electrical Pty Ltd

Test Tone Oscillator for Sydney suburban, interurban and Tangara fleet

The Test Tone Oscillator is a device, which generates a sequence of audio tones and white noise. The output is connected to the train's PA system in such a way that the test tone is heard over all inside speakers in the train. The TTO is started by the guard in the active cab and will run for 12 minutes, unless turned off in the active cab or by operating the door trainlines from anywhere in the train. This gives the guard ample time to walk through the train and verify the correct operation of the PA system.

The TTO has been delivered in two versions, one for the suburban and interurban trains and another for the Tangara train.

It is powered from the train's battery voltage (120VDC). As well as various inputs and outputs, it has a balanced audio output with a fixed audio level to suit the application.

On the Tangara train, a dedicated breakout box had to be designed in order to easily access the necessary control- and audio signals to operate the TTO.