Thanks for the reply!

I was thinking along the same lines. It was brought on by getting a Christmas gift: A wired headset for my iPhone. It works very well, and I much prefer the wired version to the Bluetooth ones, which always have sounded terrible to me. This one uses a single earpiece, but earbuds work, and I'm sure there are stereo earpiece/microphone units available.

So the hookup would be simple if there is an auxiliary port on the radio. I have seen some adapters advertised to connect iPods, iPhones and the like to Becker radios, but nothing is mentioned about the microphone line.

Is connecting a microphone in addition to the audio lines standard for all 3.5 mm cables/ports, or does one have to be careful? I've not found any pinouts yet to check.