I/O hardware, control of external transistors

[jim stockford <jim@well.com>]

Hiya,
   I'm with a team building custom PC 104 form factor, low
power computers for remote locations. The CPU is
Pentium II class, the OS is Debian Linux.
   We want software control over three different transistors
(screwed to the inside of the case).
   We're having trouble figuring out what features (in the
kernel, or device drivers, or external commands, or some
package for some language such as perl or python or
some C libraries...) give us control over logic levels of pins,
and which pins (serial RS-232, parallel, what?).
   Anybody got experience with this stuff?
jim  jim@well.com