Interest in TTY interfacing or PDP-8 W076 and/or M452 replacements/enhancement cards?

From: vrs <vrs_at_msn.com>
Date: Tue Nov 11 05:18:10 2003

> Hi Vince,
> a possibilty would be to publish the pcb-layouts and the part-lists.
> Andreas

That is certainly a possibility. The problem is that the barrier-to-entry
for obtaining the technology would remain pretty high. Only those with the
capability to create their own boards would be able to participate. I
expect there are those who would like to get their 8i/8L/TTY working (or
working better) without that hassle. The need to create an edge connector
for the PDP-8 boards means perf-board technique is not generally adequate
for them.

I am actually trending toward an opinion that the PCB board manufacturers
earn their money, since even the single unit prototype prices are only about
$30 (plus shipping) per board, vs. hours of work for me to photo-etch, cut,
drill, stuff, and debug each board. There is also equipment involved -- not
everyone has a darkroom, a bandsaw, and a drill press. (I'll grant they
probably do have soldering capability :-).)

I had expected that if there was sufficient interest, an archive site could
be talked into carrying the schematics/layouts/parts-lists. (There are
issues of file formats.)

Still, it beats having me working alone in my basement, so I'd want to find
a way to publish the information even if there isn't sufficient interest for
a board run. (Let me know if you want the information now, and if you can
read EAGLE formats.)

It is essentially a MAX232A and a quad opto-isolator (plus passives and
connectors) for each of the converter boards. The oscillator board takes a
5.0688Mhz resonator can, a mess of TTL ICs, (3x74LS393, 2x74LS86, 7440,
74LS151, 74LS157, 74123), and lots of bypass caps :-).

Thanks,

    Vince
Received on Tue Nov 11 2003 - 05:18:10 GMT

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