[GreenKeys] question about TTY signals and Telephone Signals
KC0NNC at aol.com
KC0NNC at aol.com
Tue Jan 3 22:52:37 EST 2006
Eugene:
I would suggest trying it, before you judge it. If the rise time of the 60
ma pulses is steep, then you might see some pulse noise getting through to the
telephone audio. this will sound like the old ignition noise we got used to
when we did not use resistor spark plugs. also
Sort of depends if the telephone system that you are using is one of the
newer solid state ones or one of the old western electric non-electronic units
such as the 2500 series. Generally if the home phone is a boat anchor, it will
be one of the better units.
I make a point in purchasing the old style western electric touch tone
phones, as they were electrically balanced phones, and would reject such
interference.
I watch for them at ham fests etc...
you can lessen the pulse skirt steepness of the rtty equipment with L/C
circuits, and/or place pulse shaping networks across the input terminals to the
selector magnets, and reduce this type of "pulse noise" you just have to
experiment with it.
But I can assure you, you won't burn up the telephone. or the house telephone
wiring by experiimenting
Also the 6 pair your house is wired with sounds like the old 1A1 and 1A2
office key system wiring. ( I also wired my former QTH with this readily available
wire. This also might be the old CAT-3 wiring. again, easy to get at ham
fests or on the open market. the fact that they only used two of the pairs might
mean that they had two teleco circuits coming into the house one for fax and
the other for voice. generally speaking the new electronic phones have the
ability to work on one pair even if they are the multi function multi line units
made by Panasonic etc.
Hope this info is helpful.
Harvey E. Smith
2020 Baculite Mesa Road
Pueblo, CO., 81001-2456
fka WA0BBG
nka KC0NNC
73's
RYRY/ZZZZ
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