[GreenKeys] More Transceiver stuff...

[Jim Haynes]

Aside from voice frequency carrier telegraph stuff, there has been some
use of tone keyers and receivers for miscellaneous remote control 
purposes.  I think sometimes they use on-off keying rather than AFSK.
I'm thinking of things like signaling alarm conditions, or using a
telephone dial to control remote equipment. CAA/FAA did a lot of that.


jhhaynes at earthlink dot net