dx'tard wrote:



No, don't think so. The CTCSS tones are 'sub-audible', that is, they are below
the range that humans can hear.

You are wrong. Not to say you are a lying.

This is a list of commonly used PL/CTCSS tones
(all in Hz):

67.0 69.3 71.9 74.4 77.0

79.7 82.5 85.4 88.5 91.5

94.8 97.4 100.0 103.5 107.2

110.9 114.8 118.8 123.0 127.3

131.8 136.5 141.3 146.2 151.4

156.7 162.2 167.9 173.8 179.9

186.2 192.8 203.5 206.5 210.7

218.1 225.7 229.1 233.6 241.8

250.3 254.1

You will see that they are very audible on a decent system. The only
reason they are not audible on systems using this tones -and some others
too- is, that they are using a high pass filter cutting all freqs below
300Hz or so.