Take the 2-minute tour ×  I want to power something using the
parallel port of on an old Dell Dimension 8200. How much current
can be drawn from each of the 8 the data pins? I have pulled a
maximum of 78mA/pin so far, but what is the upper limit? Can I
short pins together to raise this limit?  EDIT: So far I see
that powering things directly is not a possibility and that
putting pins together is a no-no. However, it would be nice to
be able to turn things on and off using the data pins, which
would mean a relay. These things draw current too, what should
be the amount of current that they are allowed to draw?
share|improve this question add comment  2 Answers  up vote 0
down vote accepted  You shouldn't do this at all. Parallel ports
aren't designed to provide any power. Their circuitry is of the
transistor to transistor type and are designed to basically
provide sufficient energy only for this function. The normal
specs that I've seen only talk about 2.5ma to 14ma max.
http://www.fapo.com/1284elec.htm As a