User Guide

PAMS
Technical Documentation
NME–3
General Information
Page 5
Issue 1 10/99
Technical Overview
The mobile is built around the DCT–3 core (originally designed for a
handportable phone) to operate in the GSM system. This is possible with
a modest extension to the hardware as some provisions for use in a mo-
bile are already included in the original core design. Some extensions to
the original design has been necessary to be able to operate in an auto-
motive environment, to include built–in handsfree operation and to use
an active handset instead of the UI flex board of the handheld.
The purpose of the baseband module is to control the phone, process
audio signals to and from the RF block and to and from the handset/
handsfree transducers. The module also includes a SIM card reader and
furnishes external data (RS232 and Remote control via AT commands)
and VDA specific control lines like BLD, AMC, CRM and IGNS.
The entire transceiver is built on a single multilayer PCB which is enclosed
in a housing consisting of a metal bottom part, metalized shield, plastic
part and a plastic top cover. The shield has different chambers to seperate
RF from BB and to prevent trouble with Emmisions and Immunity tests
during TA testing. Most components of the baseband section are surface
mountable and are soldered using reflow.
The transceiver has three connectors.
– 32 pole connector which basically implements the car manufacturer
recommendation for a GSM mobile phone, RU–HS connection, line–out
connection.
– A 9 pole connector for data transfer.
– The RF connector for the antenna.
All internal connections on the board are by PCB wiring. The SIM card
reader is soldered to the board.