SDRSowa for Android

Decoders

CTCSS and DCS tones

See the sub-audible tone or code that a two-way radio channel uses.

On this page

What it does #

Many two-way radio channels send a quiet tone (CTCSS) or a digital code (DCS) under the voice, so that only radios set to the same tone or code open their speaker. You cannot hear it, but the app can read it. It tells you which tone or code a channel uses.

Where to find it #

  • Home: in the NFM mode the tone or code is shown next to the band name, for example CTCSS 88.5 Hz or DCS D023N.
  • Scan: an NFM channel row shows a small box with CTCSS and the tone, or DCS and the code. See Scan.

Tips #

  • The tone appears after about a second of signal. It is shown only when it clearly stands out.
  • All decoders Every decoder in the app, in groups, with a link to its page.
  • Scan Sweep ranges or your saved stations and stop where something is on the air.
  • Home The radio itself: frequency, play controls, spectrum, waterfall and the receiver controls.