Hi Bob,

> >Inverted?  How so?
>
> I guess it must not be. I recall reading that RA4 is inverted when used as


I think someone has just thought it is inverted because you classically
drive it LOW to energise a relay connected to a +ve voltage.  The
function is inverted but the pin polarity is the same as all the
others.

> Now if only IBM had kept all the input pins on the printer ports the same
> polarity, I'd be walking on Cloud 9. Wake me up when the ride is over!

They wanted certain levels on the port after a hardware reset,
Probably found that if all the pins were high or all low the
printer they had would hang or something, or the select in and
Strobe line polarities did not make sense at the same polarity.
Might have something to do with multidropping of the printer
port to two printers or two computers way back when.

Cheers     *<<<-|
--
Kalle Pihlajasaari   kalle@ip.co.za   http://www.ip.co.za/ip
Interface Products   P O Box 15775, DOORNFONTEIN, 2028, South Africa
+ 27 (11) 402-7750   Fax: 402-7751    http://www.ip.co.za/people/kalle