CTCSS Decode should be on all analog audio modules. The code was written already and only implemented on NFM - so it should be ...
freqs_ctcss_1 = [67.0, 71.9, 74.4, 77.0, 79.7, 82.5, 85.4, 88.5, 91.5, 94.8] freqs_ctcss_2 = [97.4, 100.0, 103.5, 107.2, 110.9 ...
The AK2345 is an IC which supports CTCSS (Continuous Tone Controlled Squelch System), compatible with TIA/EIA-603 standard.
To allow multiple users to share one carrier frequency, many handheld transceivers employ Continuous Tone Coded Squelch System ...