http://pdftown.com/pdf-ebook/MB%20Phone%20Manual%20v4.6.pdf
This manual was written to familiarize the Mercedes-Benz Service Technician with the telephone system designed by Motorola for Mercedes-Benz MY00 thru MY05 vehicles. It is recommended that this training manual be reviewed prior to performing the installation of the telephone package. This document is not an installation guide or procedure, a separate Mercedes-Benz manual has been created for that purpose. However, basic troubleshooting charts are included as a part of this document to assist in correcting problems that may occur.