On Saturday 01 March 2008 23:51, Brent Hilpert wrote:
"Roy J. Tellason" wrote:
I do indeed have a board around here someplace
that I have no info on,
but it's got a row of those -- 12? -- and the outputs of them seem to be
coupled to a couple of 7400 chips.
..early DTMF decoder perhaps?
I was thinking so, the input is fed through what could be a phone line
transformer, not too different from what I've seen on some internal modems.
(although the count should be 7 or 8 for DTMF).
I could be mis-remembering that part, too. It's been a while since I've seen
it, a couple of years anyhow.
Alternatively, some proprietary radio
signalling/control stuff used
multiple tones.
It's a fairly populated board, for only being 4 or 5 inches square, with
lots of stuff on it besides what was mentioned. I recall 2 or 3 TO-220 or
TO-202 devices, a bunch of smaller transistors of assorted types, and a
couple of handfuls of discrete components. It'd be nice if I knew what it
came out of, then it might barely be possible to get some info on it
without having to laboriously trace it out.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin