Below are several videos of my TETRA experiments. The configuration that has been running trouble-free for years consists of a Motorola MTM5400 functioning as a DMO repeater. The advantage of the MTM5400 is that, in repeater mode, it can still be used simplex with speaker and microphone. Incoming and outgoing audio is routed to a Raspberry Pi 1B through a USB audio interface. In addition, the PEI interface of the mobile radio is connected to the Raspberry Pi via a serial-to-USB converter (3.3 Volt!). Through this interface, serial data is exchanged, which is used, among other things, to control the SVXLink squelch and to pass control commands and GPS data from the mobile radio to the Raspberry Pi.
A standard, up-to-date version of SVXLink runs on the Raspberry Pi. The serial communication is handled by a self-written Python script, which communicates with SVXLink via a pseudo-TTY.