On interfaces, paper tape readers/punches,

[Roy J. Tellason]

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"
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Information is more dangerous than cannon to a society ruled by lies. --James 
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