Advance port question: LPT pins voltage ...

[HadiRezaee]

Hi all, my question is more like electronic questions but it is easy ...
I wanna send some data to LPT, directly.
I don't want to print data on printer, i just want to send data to LPT, ok ?
Well, i have not problem to sending data (I used _outp function, and my OS is Win98).
I just want to know, when i send a Byte to LPT then i send a voltage to LPT pins ???
Look, first i got the pins voltages from LPT1 by Multi Meter Digital, it is a instroment which can show the voltage to you.
It is result:
Pin 2 (data pin 1) to Pin 9 (data pin 8): voltage is variable between -0.59 to +0.60
ok ?
Then i sent a data (a Byte like 0x55) in enormouse loop ...
Then i got the pins voltage again, but i got the same result (-0.59 to +0.60) !!!
Now, i wanna know did my data send in LPT port ???
Why the pins voltage didn't change ???

Please help me ...
I need fast reply

 

[mingis]

Try to load signal pin you test with a terminator resistor, let say 1.0 kOhm.

 

[mingis]

Try under pure DOS first (if you have some compiler there).
Try also delete LPT1 port definition from Control Panel/System/Device Manager/Ports.

 

[HadiRezaee]

Thank you for your helps