I am using Yahoo Voice for phone out. Headset is Logitech premium 350 usb.

My G4 iBook and Desktop, running OS 10.4.3:

The headset sounds fine for music, system sounds, etc., and the mic works. When phoning in or out the mike works, but sound will not come through the headset.

My MacBook, running OS 10.5.8:

The headset sounds fine for music, system sounds, etc., and the mic works. When phoning in or out the mike works, but sound comes through the headset like Mickey Mouse.

What the h is going on?