CTCSS / DCS tone reference
CTCSS tones do not provide privacy. Anyone without a tone set hears everything you say. Tones only control when the receiving radio's squelch opens.
CTCSS Hz Motorola Midland Kenwood
DCS codes (digital-coded squelch)
DCS sends a low-speed digital word instead of an audio tone. Radios use the 104 standard codes below, usually written with a D prefix and an N or I suffix (D023N). N means the code as listed; I is its electrical inverse — if two radios can hear each other but the squelch never opens, try the inverted setting on one side. Like CTCSS, DCS is not privacy: anyone without a code set still hears everything.