Back in 95, I used to work at a car audio place which had a close working relationship with the local acura/honda dealer.
At the time, the in-dash cell phones were not a hot selling item. They used to retail for $600(analog no less!)
I picked mine up at cost from acura for $200.00
I used my teg to pick up and drop off customers whose rides we were working on. People with ferraris, jags and Porsches got a kick out of my phone, since they didn't have this option at the time in their cars. Mercedes came out with one later on, but it sat in the top of the dash and was kind of awkward to use.
My in dash phone is just a novelty now. I haven't had service on it for quite sometime, but people still get a kick out of it.
The way it functioned;
The left front speaker would be used to hear the caller's voice, the privacy handset was installed in the center armrest compartment, the mike is on the driver's side pillar near the visor and the antenna is mounted on the front windshield.
If you want to see most of this layout (the phone and antenna) visit my imagestation album using the link on my profile.