[sci.electronics] HP printer data format/protocol?

mjj@stda.jhuapl.edu (Marshall Jose) (03/14/91)

I've wanted for some time to be able to post some HP-42 programs while
introducing as few errors as possible in the transcribing process.  I've
been thinking about capturing the IR data which is normally intended
for the printer.

On a hunch, I took one of those Radio Shack IR receivers typically used in
home-entertainment stuff, and which assumes the data is PCM'd on a
40 kHz carrier.  My hunch was right: I saw nicely-formed 2400 baud
serial data on its output pin when I pointed the calculator at it.

Does anybody know what the protocol is for this data?  If it's not
too bizarre, I think it'd be the bee's knees for what I have in mind.

Later,
Marshall Jose  WA3VPZ
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