This is not for a PC application. It will be driving a PIC. I'm looking at reading it like a quadrature encoder (I've already used the uart on the PIC). It's to be a production unit, so I'd like to avoid having mouse guts in it... Harold -- FCC Rules Updated Daily at http://www.hallikainen.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist