: OK re. the CB-thing, I know others who used to do that in developments
: with garage door openers.
Many of the older ones, especially Telectron (many in my collection)
operated by a tone on 27.255 MHz, CB channel 23. With the dramatic increase
in CB usage beginning in the late 60's, they moved up to 250, 275, 290
MHz...
Older Class C paging alarm systems could be triggered at will by either
recording their transmission or carefully whistling their sequential tone
code. Great way to annoy a neighbor at 2 A.M. You can also whistle various
tones at an End Of Train Device (replaced cabooses) and get various
responses.
Interesting side note. The Telectron VHF receiver and small leather-bound
transmitter, a little smaller than a pack of smokes was used by Mamie
Eisenhower to summon Secret Service in case of an emergency in the White
House.
Kurt
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