14 Dec
2015
14 Dec
'15
4:21 p.m.
On Tue, 15 Dec 2015, Mike Ross wrote:
Maybe, but Selectrics aren't exactly fast devices;
there's a whole lot
of potential 'no, wait, I'm not ready!' conditions. Would they all be
ORed onto one pin?
possibly. It's been done that way before.
That was my conclusion too. The old Western I/O ads
I've seen
definitely refer to it as having an 'ASCII' or 'parallel' interface.
Assuming they only ever made the two models; I suppose it *could* be
some variant of RS232, with very non-standard pinouts - but the ads
are specific; they made a smart terminal with 6800 CPU & serial
interface, and a dumb printer with an 'ASCII parallel' interface. And
that's all I have to go on, beyond prodding the hardware.
REMEMBER, "ASCII parallel" does NOT necessarily mean
"centronics-style",
as was used on TRS80, IBM PC, etc. "Centronics-style" was a good system,
but it was NOT the only one.
"ASCII parallel" could just as easily mean SEVEN bit, with a bit or two in
each direction for handshaking. "ASCII" was SEVEN bits, not EIGHT.
That would be well weird. Still trying to work out what exactly it was
intended to hook up to; a standard parallel port with a special cable,
There was a time, 35 years ago, when "standard parallel" was an oxymoron.
leads, 7 lines... I'd expect to see 8 data lines
all going to the same
place if it was anything resembling standard Centronics but with a
weird pinout. So I'm scratching my head still over just exactly what
it was supposed to hook up to.
something other than "Centronics"?