The following emergency communications channels are recognized:
- Channel 9 on CB is routinely monitored by emergency services and non-governmental organizations.
- Channel 20 on FRS and GMRS radio. (For geeks, that’s repeater out 462.675 MHz, repeater in 467.675 MHz, and 141.3 Hz squelch.)
- Channel 16 (156.8 MHz) on VHF radio.
- 2182 kHz on HF radio.
Some pieces of equipment have special distress functionality, primarily marine equipment. For example:
- DSC-equipped marine radios have a distress button. Upon activation they transmit a digital distress signal overVHFchannel 70 orHFbands.
- Inmarsat’s Inmarsat-C satellite Internet device also features a distress button.