[Kenwood] Assistance needed with microphone connections

Mon Oct 4 15:41:56 EDT 2004

Perhaps someone on the list can assist. I seem to have misplaced may manual
for a TM-455A/E (Similar to a TM-255A/E). This unit uses an 8 pin modular
connector for the microphone, and the stock mic (has no number on it) is one
with DTMF pad, PTT. up-down buttons and four function buttons. I am hooking
up a headset, and need some info. Web searches provided pinouts, but I need
to know if the PTT is part of the MIC circuit (2 wires for PTT and MIC
audio, like many portables) or if PTT is independent of the mic audio (3 or
4 wires for PTT and Audio, like a TS-830)? Also, is the power for the
electret on the audio lead from the radio or is it derived in the microphone
from the 8V lead?
My guess is PTT is separate and MIC voltage is derived off the 8V line and
NOT fed down the audio line. Can someone confirm? Thanks. --Mike, WV2ZOW