Posted by Rob on 15, 2000 at 11:53 AM:
In Reply to: HAPP Trackball, active low or active high? posted by Rob on 14, 2000 at 5:50 AM:
I will answer this one by my self (the answer might be useful to someone else)...
I wrote a mail to Hagstrom Electronics about the KE72-T trackball interface. I quote their answer at the end of this message (note. I got their accurate reply just minutes after I post it, thats customer service!).
So I guess from the answer that the HAPP trackball is "active low" since that's what the KE72-T supports (and it supports a HAPP trackball). I also guess that any standard arcade trackball (active high or low) might work with the KE72-T with the mentioned resistors...
----8<----[Quoted answer from Stan at Hagstrom Electronics]----
"Dear Robert,
Thank you for your email. Our KE72 supports "active low" trackballs.
However, it can be made to accept "active high" trackballs by placing 2.2K
ohm resistors on each of the four trackball signals to ground. In the future
our KE72 Keyboard Encoder will contain a jumper selection to allow for
"active low" or "active high" trackballs to be used without doing the
modification mentioned above."
----8<----[End of quote]----