What is the voltage supplied by an ordinary parallel port?

[jeremytaffy]

I just want to run an led between one of the data pins and ground pins. What is the max voltage? is there a place where I can get specs?
thanks in advance...
j

 

[JimInKS]

Try looking here:

http://www.beyondlogic.org/spp/parallel.htm

 

[edfair]

Data pins 2 ro 9 at +5 , negative going data pulses , pin 1 strobe negative going pulse, ack is to be negative going on 10, grounds at 18 to 24 if I remember correctly. And the other part is that the + for data and strobe is through 330 ohm to +5. Ed Fair
unixstuff@juno.com
Any advice I give is my best judgement based on my interpretation of the facts you supply. Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[Guest_imported]

Use a low current l.e.d. as the parallel port interface is not designed for powering indicator devices. Damage could occur if you trying pulling too much current out of it...


ROGER - GØAOZ.

 

[edfair]

probably would be better if he used a small power supply and a 74ls244 or similar(preferably inverting) to get the current requirements away from the parallel port.
His problem is getting the data he wants to display. will have to common the outputs thru diodes to create the plus voltage across the unused data lines and diplay from the negative data line. And if he is going to have more than 2 data leds he will be forced to go the external supply because the 6 dropping resistors for the plus will make the display unstable. Ed Fair
unixstuff@juno.com
Any advice I give is my best judgement based on my interpretation of the facts you supply. Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.