MIKE ROSS wrote in a message to Terry Vernon:

 MR> The interesting bit about the original IBM PC printer port was that
 MR> the I/O chip was a 74LS373 (4) octal buffer, a bi-directional IC.

Eh?  That's an 8-bit latch,  nothing more.  There's *nothing* bidirectional
about it...

 MR> It was originally hardwired for output only by grounding the 
 MR> direction pin 1.

I think you are mistaken here.

 MR> Many people noticed that all which was required to make the port 
 MR> bidirectional was to wire this pin 1 to a spare bit in the control 
 MR> port to make the direction bit available in software, via its hex 
 MR> latch (74LS244) spare pin 15.

The '244 is not a hex latch: "Octal Buffer/Line Driver/Line Receiver
with Non-Inverting 3-state Output" -- there's no latching in there.

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