Circuit Description - Tait TM8200 Accessories Manual

Figure 17.1 TMAA10-04/TMAA10-05 to radio interface
17.6

Circuit Description

TM8100/TM8200 Accessories Manual
© Tait Electronics Limited August 2005
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The remote microphone signal is amplified by a pre-amplifier in the
auxiliary connector plug. The power supply to this amplifier is provided by
the +13.8V supply on the auxiliary connector. This supply is filtered and
regulated down to approximately 3.3V. The reference voltage for the
regulator is provided by AUX_GPIO4 line.
The remote microphone signal is fed via AUX_MIC_AUD and an input
selector to the radio's internal microphone amplifier. The microphone input
selected depends on the PTT source used to make the call. If the remote PTT
is used, then AUX_MIC_AUD is selected. If the control head microphone
PTT is used, then CH_MIC_AUD is selected. Test points for all other
auxiliary connections are provided on the auxiliary connector plug PCB to
facilitate the connection of other devices or signals e.g ignition switch signal.
TMAA10-04 Remote PTT Kit and TMAA10-05 Hands-Free Kit 129