I don't know anything about the "NO switch" model.
I have two different ones (FSOT) BOTH are labeled as being model SC817.
They are from IQ Technologies, 11811 NE 1st St, Bellevue WA 98005. Each
has a male connector at one end ("Computer") and a header for connection
of a cable at the other end ("Peripheral"). The docs mention an
alternative model with a female connector at the computer end (for the
"new" IBM PC?)
One (earliest?) has a two position slide switch and three red LEDs,
labelled 'M', 'T', and 'D' You are supposed to try both positions of the
switch to find the one where 'M' and 'T' light, and 'D' flickers.
The other has a two position slide switch, a three position slide switch,
two green LEDs, one red LED, and two yellow (tri-state?) LEDs. You are
supposed to set the three position switch in the middle, and set the two
position switch so that both yellow lights glow; then, if one of the green
LEDs glows, slide the three position switch towards it. The red LED is
supposed to flicker.
> > 1,2,3,4,5,6,7,8, and 20. 1 and 7 are ground (chassis and signal). It
On Sat, 14 Apr 2001, Tony Duell wrote:
> Is it known that's all it connects? That's not even going to work with
> some printers (see mu earlier messages about printers that use pin 11 as
> 'busy').
I stand corrected; the docs obliquely mention "pin 11 or 19" (but only
mention them as being what the "print buffer full signal polarity switch
in the printer might be called" That reference to the switches in the
printer is the ONLY mention of individual RS232 signals.
> ways (so that a cross between, say, 20 and 5 is what's needed -- rememebr
> that HP82164) then I can't see any easy way to automatically work out
> what connections to make. I wish there was -- it would save me a few
> hours with a breakout box sometimes.
Hmmm. that sounds like a task for a dedicated microcomputer, made from
say a Compaq luggable, with a program to try a lot of combinations and
sense which ones produce results. Then display/print a diagram of what
cable configuration worked in its simulation. It would be nice if the
"smart cable" were documented for "programmers with soldering irons" as to
what cable to make to replace the device (they expect you to leave the
device in place).
> Indeed. It sounds like another of those automatic solutions that covers
> the easy cases and makes a right mess of the complex ones. A lot of
> modern products are like that....
In most cases, trying this device won't hurt anything. So using it to
solve the "easy cases" wouldn't be a problem.
My first experience with RS232 cabling (connecting a DTC300 daisy wheel
printer to a TRS-80 expansion interface) without any special tools took
weeks before I knew enough of what I was doing to get ink onto paper.
Thank you, Tony, for a reminder of how to proceed.
--
Grumpy Ol' Fred cisin_at_xenosoft.com
Received on Sat Apr 14 2001 - 20:53:10 BST