Re: [CAD_CAM_EDM_DRO] checking parallel port

Hugo:

I imagine at least MOST PC's made in the last ten years have about the same
parallel-port output IC. I haven't "dug into one" to see, but this one I
have condemned to running machines using ONLY GWBASIC (MSDOS, Windows 95
DELeted, now) will COMFORTABLY put out at least 7 mA on all-8 printer-bits
simultaneously. So, I have 8 good new small (T1 size?) LED's in series with
1K resistors to the 8 data-bits, and the cathodes of the LED's all to the
printer-port ground. To check this "checking system", simply type "OUT
$378,FF" or "OUT 888,255 in GWBASIC, and hit RETURN. ALL-8 should light up.
There a few "input pins" as well, and you can simply "pull those up" with a
2K7 R (each), and test the inputs (@ 889) by grounding the individual pins.
Which they are you can find yourself; not my point, here.

Jan Rowland