Repeater (stations) need to idenfiy every 10 minutes while it's on the air. This can be done by the users however, the better way is automatically by the station itself. There are a couple of (old school) manufactors; VHF Engineering and Hamtronics. Both are long gone, since the 1970's however there may be used ones on line. Here's a comparision on the two brands as shown here.

Shown here is the Hamtronics brand in stock form. It will need some additional circuits to work with the System.

Here shown is the 5 v regulator, AF output interface and trip circuits added:

Here shown is the VHF Eng. brand as stock form.

Here shown is the VHF Eng. brand set up for SRG.

Here shown is the interface to work with SRG at one site.

Here's another brand made by Communications Specialist; the ID-8. Too bad they no longer make them, however, from the used market is possible. They work well and have a small "footprint" for mounting on your station. Programming is fairly straight forward if you take the time and patience to read the manual which is only 4 pages. The Author has 2-3 of them in service. Shown here the unit is being programmed on the bench at the shop. Later, it will be installed at the remote site. This image shows the OEM keyboard that comes with the unit. Pay attention to the orientation of the plug-socket. Pin 8 is ground towards the PCB edge. All settings are done with the keyboard, except for the audio output level which is controlled with a small pot on the PCB.

Shown here the Author built a custom keypad with a cable to help with tight areas during programming, such as the Micor compa control shelf. The wires are resistor color code. Pin 8 is "gray" or white, indicating ground (or common) which goes to the near PCB edge as said above.