I want to control an electronic switch that needs a couple of TTL level
signals. It is possible to use a Sun for this? I was thinking about
programming the parallel port, which has in the past been used in PCs,
but I'm not sure how easy it is on a Suns - I have a feeling it is not
so easy.

Suns available include a SPARCstation 20, Ultra 60 and Netra T1. Speed
is not an issue and I dont mind sticking a transistor on the output if
needed.