Help! Auto switch box and Canon Multipass 2500

Most auto switch boxes will not work with two devices unless they have a
manual switch as well, from which you can specify  a or b. Sorry, don't
know what a quickcam is but most auto switch boxes that work with two
printers will not work with other devices. Also almost all auto
switch boxes have problems with true bi-directional devices also
known as bi-tronic. Best suggestion is to either use a manual switch box
with full 25 pin switching or add another parallel port or, if you want
what you want and are prepared to pay for it - check out some specialist
switch box companies. Note: that Canon is probably right about their
device not working with auto switch boxes.