Re: [CAD_CAM_EDM_DRO] Parallel Port Woes

In a message dated 05-Aug-02 18:47:34 Central Daylight Time, tom@...
writes:

> Lesson learned: New LSI printer port chips may not have enough pookey
> to drive a TTL load or an optoisolator input. If you are having funky
> things happening with the parallel port, maybe a buffer chip is in
> order!

I had put a 75HCT541 (8-bit buffer) on the Printer Port Date Lines every time
I attached anything thereto, after first experiencing the PP output of an old
"true TTL" '286 antique! For driving relays or opto-isolator inputs
(which are just LED's!), I will often then use such as a ULN2003 after that
(open-C Darlingtons). GOOD lesson!


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