MDC-1200 radio ID burst
A short data burst at the start or end of a transmission that identifies the radio.
What does it sound like?
A quick 'brrrp' at the beginning or end of someone speaking.
Who uses it?
Businesses and public agencies using Motorola-style radios.
Where and when can I hear it?
VHF/UHF FM channels.
The science
MDC-1200 is a short data burst sent at 1200 baud over an ordinary FM voice channel, carried by switching between two audio tones in a form called minimum-shift keying. Each radio has a four-digit hexadecimal ID. A radio can send its ID at the start of a transmission, at the end, or both.
Why use it?
It lets a dispatcher see automatically which radio is talking, and it adds features such as an emergency alarm, call alerts, radio checks and selective calling over existing analog FM channels.
Lore
MDC stands for Motorola Data Communications. In Motorola's MaxTrac mobile radios, the factory default ID was simply the last four digits of the radio's serial number.
What do the decoded parts mean?
- Unit ID: The number of the radio that transmitted.
Easily confused with
- Selective calling tones: selcall is a run of musical tones
- Touch-tone (DTMF): touch-tones are pairs of pure tones