Power is supplied from the Audio Fuse in the rear junction block via CKT 2240 (ORN) to the cellular telephone module at terminals 4 and 16. The module is grounded at terminals 3 and 17 via CKT 1051 (BLK) to ground G401.

The cellular telephone module contains the cellular telephone transceiver and the cellular telephone modem. The module controls the cellular telephone handset power via CKT 1941 (BRN) and regulated 8 volt power CKT 1266 (RED). The module controls the handset display and receives handset/keypad data on CKT 679 (PPL), CKT 1156 (PPL/WHT) and CKT 1798 (GRY/BLK).

Power is supplied to the cellular telephone handset at terminal 5 from the ACC Fuse in the underhood junction block via CKT 43 (YEL) when ignition is in RUN or ACC and during retained accessory power. The handset is grounded at terminal 10 via CKT 651 (BLK/WHT) to ground G300. The handset contains a keypad, display, microphone and ear speaker. The handset communicates shielded signals to the cellular telephone module as follows:

When the handset is place in its docking cup, the phone operates in the hands-free mode. This mode allows the driver's voice to be received by the roof-mounted microphone. During hands-free mode, the vehicle radio mutes and the incoming cellular telephone audio is routed through the radio's speakers. When the handset is removed from its cup, the hands-free feature is disabled and the radio is unmuted. The handset must be held to the driver's head for voice conversation.

The cellular telephone microphone is wired to the cellular telephone module via CKT 655 (GRY) and CKT 814 (NAT). During hands-free operation, the module provides mono audio output to the vehicle audio system on CKT 658 (DK BLU) and CKT 659 (BLU/BLK).

The module communicates on the Class 2 serial data line CKT 1807 (PPL), which the module uses for transmission of messages, status and diagnostic information.