Useful table for ham radio people:
Continuous Tone Coded Squelch System (CTCSS) Tone Squelch for communications aka Subchannels
https://www.hamradio.me/charts/ctcss-radio-squelch-tones.html

All this CTCSS stuff really is is a tone that is sent along with your voice to the receiving radio.

#amateur_radio #ctcss #radio #repeaters #tone_reference