Connecting radios all over the world

MVP - External Connections

Connecting to other systems

Connections

This is needles to say something that needs to be tailor made for each project. For the Stockholm Metro project we needed to use connections both to old trains, 50+ years with relay closures as well as “modern” on board computers, in the newer trains, with serial bus connections.

All audio from the train microphones and audio to the speaker goes through the panel to the radio. As well as audio to the train PA system.

To interface with the Tetra radio we use the radios PEI-port. This is basically a serial port using AT commands and is more or less standard on all Tetra radios from different manufacturers.

We also have a USB port that is used for programming of the panel.

Back side of the panel

The Connectors

  • Power connector
    Works from 11-16VDC
    Consumes max 1,5A, typical 0,3A standby
    Protected for power dips up to 0,5 seconds 
  • Programming connector
    This is a USB connector used for upgrading of firmware and setting parameters.
    The port could also connect to other peripheral units if needed in the future.
  • Interface connector
    In this connector all train systems go in/out. Here are audio from train microphones, audio out to train PA. Serial data to train systems and relay closures to the old trains.
  • Radio connector
    This connector goes directly to the radio and includes PEI commands and audio.
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