Cellular Phone: Description and Operation

ONSTAR DESCRIPTION AND OPERATION
This vehicle will be equipped with either the 2.0 or 2.6 version of the OnStar(R) system. Both systems consist of a Vehicle Interface Unit (VIU), Vehicle Communication Unit (VCU), GPS antenna, cellular antenna, microphone and OnStar(R) button assembly. Both the Systems interface with the vehicle audio system.

The OnStar(R) system version 2.0 provides the customer with impact detection, navigation instructions, emergency services, stolen vehicle tracking and recovery service, roadside assistance, door unlock, light flash and horn pulse.

The OnStar(R) system version 2.6 provides all the same features as version 2.0 with the addition of a hands free cellular phone. The OnStar(R) Personal Calling feature, if equipped, uses voice commands for dialing and programming.

VEHICLE INTERLACE UNIT (VIU)
The Vehicle Interface Unit (VIU) is powered by a fused battery positive voltage circuit, connected through vehicle wiring to the 3 button assembly, radio, microphone and the Vehicle Communication Unit. It is also attached by means of a coax cable to the GPS antenna. Ground for the module is accomplished by means of dedicated circuits that are routed with body wiring systems to chassis ground points. The VIU also houses the cellular and GPS modems to process data from the GPS satellite system and VCU. The VIU communicates with the rest of the vehicle over the class 2 serial data bus. Power moding for the VIU is accomplished over the class 2 serial data bus on some vehicles or the ignition 1 voltage circuit on others. The VIU also has the capability of commanding the horn, door unlock and exterior lamps using class 2 messages. For vehicles without this capability, the VIU uses specific, discrete circuits for commanding these features. When an OnStar(R) keypress is made, a class 2 message is sent to the audio system to mute all radio functions and transmit OnStar originated audio. On vehicles that do not use class 2 to communicate with the audio system the VIU uses the Entertainment And Comfort (E & C) serial data circuit. After the audio system is muted, the OnStar(R) audio is transmitted to the vehicle audio system on the remote audio right signal circuit, the remote audio left signal circuit, and remote audio output (-).

VEHICLE COMMUNICATION UNIT (VCU)
The Vehicle Communication Unit (VCU) is a 3 watt cellular transceiver that connects the OnStar(R) system to the cellular carrier's communication system. This module handles all cellular operations, sending and receiving all communications over the cellular antenna and cellular antenna coax. Power and ground for the VCU is provided by the VIU on the battery positive voltage and ground circuits. The VIU also supplies ignition voltage to the VCU over the ignition 1 voltage circuit. The VCU communicates with the VIU by using the OnStar(R) serial data (-) circuit, OnStar(R) serial data (+) circuit and the OnStar(R) serial data return circuit. The callers voice is carried to the VCU using the microphone signal circuit and the drain wire circuit. The audio signal is carried from the VCU to the VIU on the audio return signal circuit and the audio low reference circuit.

ONSTAR(R) BUTTON ASSEMBLY
The OnStar(R) button assembly may be part of the rear view mirror on some vehicles and a separate unit on others. The button assembly is comprised of the three buttons and a status LED. The buttons are defined as follows:
^ The Answer/End Call button, which is black with a white "dot", allows the user to answer and end calls or initiate the personal calling feature if equipped.
^ The blue OnStar(R) Call Center button, which displays the OnStar(R) logo, allows the user to connect to the OnStar(R) Call Center.
^ The red Emergency button sends a high priority emergency call to the OnStar(R) Call Center when pressed.

The OnStar(R) button assembly receives ten volts on the keypad supply voltage circuit. When pressed, each button completes a circuit across a resister allowing a specific voltage to be returned to the VIU on the keypad signal circuit. Depending upon the voltage range returned, the VIU is able to identify which button has been pressed.

The OnStar(R) button assembly status LED is green when the system is on and operating normally. When the status LED is green and flashing, it is an indication that a call is in progress. When the LED is red, this indicates a system malfunction is present. The OnStar(R) LED is controlled by the VIU over the keypad red LED signal circuit and the keypad green LED signal circuit.

ONSTAR(R) MICROPHONE
The OnStar(R), or cellular, microphone can be part of the rear view mirror assembly or, on some vehicle lines, can be a separate, stand-alone unit. In either case, the microphone is supplied voltage on the cellular microphone signal circuit, while voice data from the user is sent back to the VIU by means of either a cellular microphone low reference circuit or a drain wire.

CELLULAR AND GPS ANTENNAS
The cellular antenna is the component that allows the OnStar(R) system to send and receive data over airwaves by means of cellular technology. This antenna is connected at the base to a coax cable that plugs directly into the Vehicle Communication Unit. The GPS or, navigation antenna, is used to collect the constant signals of the orbiting satellites. Within the antenna, is housed a "low noise" amplifier that allows for a more broad and precise reception of this data. Current GPS location is collected by the module every time a keypress is made. The OnStar(R) Call Center also has the capability of "pinging" the vehicle during an OnStar(R) call, which commands the module to retrieve the latest GPS location and transmit it to the OnStar(R) Call Center. A history location of the last recorded position of the vehicle is stored in the module and marked as "aged". In the event the VIU loses or is removed from power, this history location is used by the OnStar(R) Call Center as a default. Actual GPS location may take up to 10 minutes to register in the event of a loss of power. This antenna requires a clear and unobstructed path to the satellites in the sky. Window tinting on vehicles may interfere with the GPS sensor functions, depending upon the amount of darkening and/or metallic particles that are embedded in the film of the tinting material.

ONSTAR(R) RECONFIGURATION PROCEDURE
Within the VIU and VCU are a set of unique numbers that identify the OnStar(R) customer and the specific vehicle the modules reside in. These numbers, the Station Identification Number (STID) and the Electronic Serial Number (ESN) are transmitted over the cellular network when an OnStar(R) keypress is made and are essential for proper identification and connection to the OnStar(R) Call Center. In the event the VIU or VCU requires replacement, the OnStar(R) Reconfiguration procedure must be performed. This procedure allows for the new STID and ESN within the replacement modules to overwrite the old numbers and update customer and vehicle information at the OnStar(R) Call Center. The Reconfiguration process is explained within the VIU and VCU module replacement procedures.

ONSTAR(R) CELLULAR, GPS, AND DIAGNOSTIC LIMITATIONS
The proper operation of the OnStar(R) System is dependent on several elements outside the components integrated into the vehicle. These include the National Cellular Network Infrastructure, the cellular telephone carriers within the network, and the Global Positioning Satellite system.

The cellular operation of the OnStar(R) system. may be inhibited by factors such as the user's range from an analog cellular tower, the state of the cellular carriers' equipment, and the location where the call is placed. Making an OnStar(R) keypress in areas that lack sufficient cellular coverage or have a temporary equipment failure will result in either the inability of a call to complete with a data transfer or the complete inability to connect to the OnStar(R) Call Center. The OnStar(R) system may also experience connection issues if the identification numbers for the modules (STID and ESN numbers) are not recognized by the cellular carriers local signal receiving towers. OnStar(R) cellular connection issues such as these require the assistance of the General Motors Technical Assistance Center OnStar(R) Group, which coordinate with cellular carriers to resolve connection issues.

The satellites that orbit earth providing the OnStar(R) system with GPS data have nearly 1,0 failures associated with them. In the event of a no GPS concern, the failure will likely lie with the inability of the system to gain GPS signals because of its location (i.e. in a parking structure), hardware failure, or being mistaken with an OnStar(R) call which has reached the Call Center without vehicle data.

During diagnostic testing of the OnStar(R) system, the technician should ensure the vehicle is located in an area that has a clear unobstructed view of the open sky, and preferably, an area where analog, cellular calls have been successfully placed. These areas can be found by successfully making an OnStar(R) keypress in a known good OnStar(R) equipped vehicle and confirming success with the OnStar(R) Call Center advisor. Such places can be used as a permanent reference for future OnStar(R) testing.

HANDS FREE CELLULAR PHONE
The hands free cellular phone is an additional feature to the OnStar(R) system. During a hands free call the microphone and audio system work the same way as a normal OnStar(R) call. When the answer/end call button is pressed, the audio system will mute, the OnStar(R) system will then return the prompt "ready". At this point there is a specific command set to initiate a cellular call. If the vehicle receives a call when the radio is on, the audio system will mute and an audible "ring" will be heard though the speakers. The call will be answered when the answer/end call button is pressed.

All the voice activated commands are interpreted by the VIU. A list of these commands is supplied in the information provided to the customer. If the information is not available to reference, at any command prompt you can say "HELP" and the VIU will return an audible list of available commands. If the customer concern is not being understood or not being heard by the OnStar(R) system, place a call to the OnStar(R) Call Center to verify proper operation of the microphone. Here is an example of the commands and the OnStar(R) system responses.

Dialing A Phone Number Hands Free:

A complete list of commands is supplied in the information provided to the customer with the OnStar(R) system.

OPERATION OF THE ONSTAR(R) SPEECH RECOGNITION SYSTEMS
OnStar(R) Generation 2.6 users communicate with two speech recognition systems. Speech recognition allows the user to speak to one computer in the vehicle, and one reached over a phone line. The computer tries to understand the user's command, and responds by speaking back, or by taking the appropriate action, e.g. dialing the phone.
1. Personal Calling uses a speech recognition system that resides in the vehicle. When the user presses the dot button, the system states, "Ready", and listens for the user's command. The user can speak commands to control the hands-free phone.
2. Virtual Advisor is a remote speech recognition system that the caller access by making a phone call. The user connects to Virtual Advisor by requesting it during personal calling use. The user is then transferred to the Virtual Advisor server and talks to it via a cellular connection.

The OnStar(R) speech recognition systems use speech technology that is designed to understand a wide range of American English speakers. Although there is no one "right" way to speak English, the system will work best when users try to modify their pronunciation should they encounter difficulty. Users who do not obtain good results are advised to try the tips and "workarounds".

General Tips For Better Speech Recognition Part 1:

General Tips For Better Speech Recognition Part 2:

GENERAL TIPS FOR BETTER SPEECH RECOGNITION

Personal Calling Commands:

PERSONAL CALLING COMMANDS