On Sat, 13 Dec 2008 10:25:16 -0800, JosephKK wrote:


You wanted a tone detector. Then you asked if a vibrating reed
(mechanical resonator) can be one. Then you said that there was not
many methods, so i named some that even did more complex things. You
asked for the discussion and received it. Moreover, the tone squelch
system does some other complex things as well. Particularly when
multiple users (groups) are on a single channel in a single locale.

I've administered business band radio systems. CTCSS is similar to a 3
tumbler keylock.