Brief Description: Bluetooth Cell Phone To Kenwood - Part 1
The Kenwood DNX8120 entertainment system has Bluetooth connectivity. This means that it will act as a hands-free interface to, for example, my Bluetooth capable Blackberry 8820 cell phone. I had tested the functionality when I was installing the Kenwood, but found that I was able to hear the audio through the airplane intercom/headsets, but that I had to use the external microphone provided with the Kenwood for the talking portion. I got to looking at this again recently and decided, kind of as I had originally, that an external mic in the cockpit wasn't going to work out both ascetically speaking and probably sound quality-wise because of all the noise from the 390cui.
So I thought, I wonder if I could somehow hook up one of the PM3000 intercom's Passenger headphone outputs to the Mic input on the Kenwood...? I knew that it wouldn't work connecting straight up since the output from the Intercom was line-level (or greater) and the mic input was looking for a mic-level source. I got on the 'ol Interwebs and did some research into impedance matching circuits. I found this really cool web site on doing just that and they had a number of formulas you could use to calculate whatever you needed.
