Omrom programmable terminal

[Chuck Guzis]

On 3 Sep 2009 at 20:41, Tony Duell wrote:

> I have (both the HP one and clones), but I don't own one. To be
> honest, it _looks_ cool, but it's fairly useless. The ones I used had
> no pulse-stretching circuitry, the LEDs just displayed the state of
> each pin (on for '1', off for '0' and on-but-dim for toggling -- the
> brightness depended on the mark/space ratio). It was OK on slow
> circuity, but that's easy to debug anyhow. On anything with a
> reasonable clock frequency, it didn't tell you much.

I can see that without pulse stretching or even a "pulse" as opposed 
to "steady state" indication that the utility would be marginal.

> HP made a couple of other devices that I don't own and could never see
> the point of. One was the 'signature analyser' which will tell you if
> a logic signal differes from the correct version (well, provided you
> have a 'correct version' to also test) but won't tell you _how_ it
> differs. So actually finding the fault doesn't seem to be any easier.

I remember reading about signature analysis in the HP Journal.  It 
looked like a promising technology--not for the lone self-employed 
technician, but for the field engineer who saw the same equipment day 
in and day out.

It's a method of automating the diagnostic procedure; in a sense, a 
predecessor to modern boundary-scan techniques.

--Chuck