In support of voice recognition on the AV macs, Apple has moved to the Plaintalk microphone. The main difference is the fact that these microphones contain a preamplifier in the microphone itself, giving superior audio quality. The longer pin provides a third connection to power the preamp. Since the new macs are expecting a greater audio level which is supplied by these new microphones, the lower levels from un-amplified microphones will not work.
One major oversight on apple's part is that the larger monitors which provide microphone connectivity on the base do not support the third pin. So, if you are using a recent model mac (including any powermac) and a monitor which extends the adb, microphone, and speaker jacks to the base, you must plug the microphone directly into the back of the mac, NOT the base of the monitor.
_/ _/_/_/ _/_/ Brad Ramsey bramsey@its.bldrdoc.gov
_/ _/ _/ Institute for Telecommunication Sciences
_/ _/ _/ Boulder, Colorado
_/ _/ _/_/ Voice (303) 497-3165 FAX (303) 497-3680