Power is supplied from the AUDIO fuse in the rear fuse block via CKT 2240 to the cellular telephone module. The module is grounded via CKT 1051 to ground G401.
The module controls the cellular telephone handset power via CKT 1941 and CKT 2526. The module controls the handset display and transfers handset/keypad data on CKT 679, CKT 1156 and CKT 1798.
Power is supplied to the (optional) RF signal amplifier from the cellular telephone module via CKT 344. The RF signal amplifier is grounded via CKT 1051 to ground G401. The RF signal amplifier is connected to the cellular telephone antenna and to the cellular telephone handset by coax cables. This amplifier may be omitted and replaced by an adapter that connects the two coax cables if desired (such as in areas of strong signal strength).
The handset communicates shielded signals to the cellular telephone module as follows:
| • | Mouthpiece audio CKT 1153. |
| • | Earpiece audio CKT 1235. |
| • | Audio low reference CKT 1155. |
When the handset is placed in the docking station, the system operates in the hands-free mode. This mode enables the hands-free microphone to pick up the the driver's voice. During hands-free mode, the radio amplifier mutes the radio or cd changer audio signal and sounds the the incoming cellular telephone voice audio signal through the speakers. Removing the handset from the docking station disables the hands-free feature, which allows the radio amplifier to play the radio or cd changer audio signal. 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 and CKT 814. During hands-free operation, the module provides mono audio output to the vehicle audio system on CKT 658 and CKT 659 .
The module communicates on the Class 2 serial data line CKT 1807, which the module uses for transmission of messages, status and diagnostic information.
