PS/2 Interface (was: Wang 300 Calc]

[Tony Duell]

> > I find that very hard to believe. I would be suprised if most (if any) 
> > signal connecotres met the approvale requirements for a mains connector.
> 
> You got me curious, so I just ran a search on Farnell's database for DB25 
> connectors rated to 500V; it coughed up 60 different ones.

IIRC some of the old Cannon D-seires connectors were rated at 750V.

However, there's a big different between 'Is rated to withstand main 
voltage' and 'is approbed as a mains connecotr' 


> 
> I can't think of an example where I've actually seen it done with D-types, but 
> I've certainly come across it on telecomms stuff before using DIL-type card 
> connectors (what I've always called 'euroconnectors', but I'm not sure what 
> the official term is)


DIN41612 connectors? The sort of think used for Nubus cards, for example?

There are many variants of those, incluiding ones iwth widely spaced pins 
(0.2"?) for mains work. That Philips machine you gave me has one on the 
SMPSU board for that purpose.

I've seen PCBs with a mains DIN41612 connecotr and a signal DIN41612 
connector alongide each other, but I've never seen a board that puts live 
mains on the same connecotr as low-votlage logic signals.

> I bought one of those wall warts with a range of interchangeable connectors 
> when I was in the US last. Seemed like a good idea at the time; the connectors 
> were reversible so that you could swap polarity just by changing the connector 
> through 180 degrees on the cable, not to mention that it came with about ten 
> different sizes of connector. (the kids were getting through batteries in toys 
> with lightning speed :-)
> 
> It was only when I took the packaging off that I discovered the flaw: the 
> terminals at the end of the cable are marked for polarity - but there are *no* 
> markings on the interchangeable connectors which give an indication of which 
> of the two pins goes to the connector's ring, and which goes to the tip. 
> Without any test gear it's random as to the polarity of the plugged-in connector.
> 

Argh!. How about 'buzzing out' each 'end' with an ohmmeter to determine 
which pin is the tip and which the sleeve, and then marking the 'tip' pin 
on each 'end' with, say, Tipp-Ex. 

The box of 'ends' I bought at Maplin each have a little diagram on 2 of 
the sides of each tip showing the polarity (opposite polarites for the 2 
diagrams on each dip, of course). The cable-mounted socket has an arrow 
on one sidem and I wired it so that points to the apporpairte diagram 
when the tip is plugged in. That maant the wire wit the the tracer stripe 
on it wen to the -ve side of the bench supply and the plain wire to the 
+ve. Oh well...

-tony