Midian Electronics’ TRE-10 is a tone remote encoder with a 600 ohm line driver, which encodes the high level 2175 Hz, F1 function tone and continuous low-level 2175 Hz guard tone and passes received audio via a dedicated phone line, telemetry link or microwave to a tone remote adaptor to key a base station or repeater. The TRE-10 will also pass audio from an audio source to the tone remote adaptor via the above mentioned link.