Would a LPT port have enough inputs and outputs to read linear encoders for 3 axis?
Yes and no:
-Yes it can read 3 axis be it A/B or A/B/Z, so 6 or 9 inputs, but only in "IN" or "X" mode that most built in parallel ports can do but not all, and you might need more than one parallel port for everything to work.
-No as parallel port is really slow for reading encoders, especially high resolution ones.
You can use a parallel port or two to do some testing and maybe very slow work, but i would not think you can use it for a production machine.
As a reference, you can do 5000-20000 encoder pulse readings per second on a parallel port with a good latency PC, might even go to 50000 with a really good latency PC, but this is to far fetched.
And for reference Mesa can do up to 10000000 pulse readings per second. Yes, that is 10 million.
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