> > Actually I was talking about the input pins. BUSY is inverted in relation to
> > PE, SELECT, ACK, and INIT.
>
> Quite, but I think the same reasoning holds here.  I expect that in
> the default mode, like with a happy idle printer plugged in and
> idle you readback a 0 or something.  Or perhaps if you write
> a 00 to the control pins the printer will respond with a zero.

For the outputs, having some of them (e.g. strobe) inverted makes a fair
amount of sense since a normal 74xx-style latch will power up in a low state;
throwing an inverter on its output will ensure that the printer is not strobed
during the time the PC is on but the BIOS hasn't yet taken control (in effect,
it minimizes the likelihood of the printer getting a garbage character).
Since outputs may have an effect even before the PC's software is in control
of the port, it makes sense to have hardware inversion to ensure things work
nicely.  The inputs, however, won't have any effect outside of what the PC
software does with them, so having them inverted accomplishes nothing other
than making things just a little more confusing for the poor developers who
have to work with 'em.