By Jim Kerr

Styling, price and performance may initially attract us to specific
vehicles, but it is the small features we seldom try out on a road test
or in the showroom that can eventually determine our overall
satisfaction level with that vehicle. One feature that has impressed me is OnStar. Available on most GM vehicles and a few other makes such as
Acura, Audi, Subaru and VW, OnStar is a communications system that can
play an important role in driver safety and convenience.

OnStar logo
Click image to enlarge

OnStar uses a combination of Global Positioning System (GPS) and
cellular phone technology. The GPS network has 24 satellites in precise
positions orbiting 10,900 nautical miles above earth. The OnStar
receiver uses six channels to receive the signals from satellites. A
small 1½ inches square antenna is all that is required to receive these
signals, as they are really only a timing signal code. Both the
satellite and the vehicle’s receiver are generating the same signal, so
the OnStar receiver can measure the time difference of the two signals
to calculate the distance to the satellite. By comparing the distance
from four different satellites, the exact position of the vehicle is

The OnStar cellular phone system uses a full 3.0-watt cellular system as opposed to the typical 0.6-watt portable cell phone. This provides
superior range, but there must still be cell phone reception in your
driving area for the OnStar system to work. Many remote or sparsely
settled parts of the country have no cellular communications. Some may
think that OnStar uses satellite communications, but that is only for
receiving GPS signals, not for communicating.

There are several versions of OnStar in vehicles. While all appear the
same, the latest offer additional features such as message recording
capability. Originally, all OnStar cellular communications used analog
signals. In 2003, Analog/Digital-Ready systems started to be installed
on some vehicles, and Analog/Digital (dual mode) units became available
on select 2004 models and all newer vehicles. Unfortunately, GM has not
made provisions for upgrades to the analog-only systems, and when
cellular communications switch to digital-only beginning in January
2008, these vehicles will no longer be able to access the OnStar system. I would hope that GM will offer an upgrade solution by that time for the many owners who have come to rely on OnStar service.

From a driver’s viewpoint, OnStar is easy to use. Press the Blue OnStar
button and the system automatically connects to one of hundreds of
OnStar Advisors in Oshawa, Ontario or two U.S. call centres. Your
location, vehicle identification and owner name are displayed on their
computer as they provide help. The mapping system used by the advisors
is better than any on-board navigation system I have ever used.

Different levels of service are offered, for a fee. The basic “Safe and
Sound” plan provides roadside assistance, stolen vehicle location,
remote vehicle diagnostics and automatic notification of air bag
deployment so help can be provided as required. The “Directions &
Connections” plan adds services such as route directions or the location of a business. All of this is done by simply talking with an OnStar advisor. The remote doors unlock service provided with all OnStar plans have aided many locked out motorists.

Cellular phone service is also available. Time can be purchased from
OnStar in blocks of minutes. Press the white button and then you can
speak the phone number or say a previously stored name. The system asks
for confirmation and then dials, all without the driver taking their
eyes off the road.

Each vehicle receives its own phone number. Someone can call you as you
drive, or you can call from vehicle to vehicle. Unlike regular cell
phones, there are no roaming or long distance charges, so if you travel
a lot, this could be the cheapest way of phoning home.

I have used the OnStar system to direct me when I was lost. I have
phoned to another vehicle while driving down the road. I have been given advice when an air bag warning light turned on. I have even had a police car come to our assistance when a malfunction in a system sent a false emergency signal. All of these features work as good or better than the advertisements portray. So far I haven’t had to use the remote door unlock feature yet, but I suspect I will some day.

GPS, cell phone and internal vehicle communications networks technology
all combine to make the OnStar system work effectively. That’s why
OnStar has become the communications system of choice for more companies than just GM.

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