PS/2 Interface (was: Wang 300 Calc]

[Chuck Guzis]

On 15 Sep 2007 at 23:40, Tony Duell wrote:

I said - 

> > I'd sure as heck would like the assurance that whatever plug I'm 
> > sticking into a receptacle at least isn't going to result in "magic 

> Since the PS/2 keyboard and mouse interfaces are electrically very 
> similar, I can see no reason why you'd let the smoke out if you pluged 
> them into each otehrs' conenctors, unless oyu plug a PS/2 keyboard into 
> one of thsoe seiral pouse adapaters and then into an RS232 port. 

No, but I didn't specify that I meant the keyboard and mouse ports 
(though there was some chatter about it.  My concern is with things 
such as printer and RS232 ports using the same connector, or putting 
power on connector pins where it's possible to insert the connector 
"upside down".  Or using a power connector and wiring it differently 
than the rest of the world (e.g. MD2 diskette drives as opposed to 
anyone's 3.5" diskette drive).  I believe that a few old Calcomp 8" 
floppies actually put mains power through the signal connector on a 
couple of models.

Wall warts are perhaps the worst examples of "user friendly" design.  
It's not sufficient that one match the voltage and current and AC vs. 
DC but one must also match the polarity.  And the markings on some 
equipment is missing entirely or engraved/printed too small to see 
clearly.  I've seen those little "tip and ring" symbols in all 4 
possible orientations.

Take a look at a dozen bits of equipment with wall warts and you'll 
note that many carry an entirely different branding than the 
equipment they power.  So matching brands won't work.  And even when 
there are matching brands, there's no specific information that a 
Sony CD player PSU belongs to the CD player and not the DAT drive 
sitting next to it.  And so on.

I have several of those "universal" wall warts and find them to be 
useful also.  I also keep a doublet (magnifier) handy for deciphering 
those connector symbols.

Cheers,
Chuck