Check radio and token operation before the train goes leaves the depot
Often, due to the remote nature of RETB routes, trains are stabled out of the RETB radio coverage area. This makes checking that a train can receive tokens over air impossible whilst it is in the depot.
The DTU (Depot Test Unit) enables train operators to check that the RETB on-train equipment can send and receive tokens and voice calls. The DTU creates a local RETB coverage area and allows depot test tokens to be configured and sent, ensuring that the train will be ready to operate when it reaches the RETB network.
With an integrated microphone and loudspeaker, the DTU can also be used to make calls, checking that the audio equipment on the train is working correctly.