On interfaces, paper tape readers/punches,

[Roy J. Tellason]

On Sunday 02 March 2008 12:35, Tony Duell wrote:
> > I do indeed have a board around here someplace that I have no info on, 
> > b= ut=20
> > it's got a row of those -- 12? -- and the outputs of them seem to be
> > coup=
>
> I assume 'those' means HE567s

Some kind of 567,  anyhow.

> > led=20
> > to a couple of 7400 chips.
>
> Had it been 7 or 8, I'd have guessed they were set to the row and column
> tones for a standard teletphone DTMF keypad, and that the logic combined
> them to produce a separate output for each key.

As I posted earlier,  I may have mis-remembered how many of them there were,  
it having been at least a couple of years since I've seen that board.

The tone decoders and gates wouldn't be too much trouble to trace out,  but 
then there's all that stuff on the rest of the board,  with no easy pattern 
to it,  and bunches of points tying to the card-edge connector.

Is there any "standard" designations for the common 44-pin edge connector?  
Any "standard" about which pins are component-side and which are solder-side? 
Common usage of any of those pins?  I haven't run across any such,  so far.


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