What is CTCSS / DCS?
Any combination of President Electronics Randy II and Harrison radios, for instance, can be enabled to communicate within off-road vehicle groups, construction crews, transport companies, and many other use cases where uninterrupted communication within the group is preferred.
CTCSS (Continuous Tone Coded Squelch System) and DCS (Digital-Coded System) are both privacy codes. They are used to share a channel without interference or cross talk.
CTCSS uses continuous tones below 300 Hz.
The receiver won't break squelch unless it hears the sub-audible tone.
CTCSS is useful when there are many radios in an area. Once a radio is set to a CTCSS code, only transmissions from other radios will be heard.
CTCSS decodes in about 250ms.
DCS is the updated version of CTCSS.
It uses digital data or encoded words that are unique to each channel.
DCS sends a number repeatedly encoded in digital as you speak. The number is repeated in low frequencies, so it is close to inaudible.
DCS is designed to eliminate interference from unwanted transmissions from other individuals or groups who are operating on the same channel or frequency.
It takes about 350ms or less to reliably decode DCS.