Depending on the model, the vehicle could be locked by pressing a point on a door handle or simply walking away.
Overrides built into the system could identify the driver even if two people with Keyless Go cards approached the vehicle. To ensure security, the keyless device had 4 billion possible security codes that changed randomly each time the vehicle was entered.
Siemens also included an safety attribute that proved attractive to vehicle owners. The Keyless Go device had to be inside the vehicle to start it. At the same time, it also prevented the door from locking if the card was inside but the driver was not.
The technology anticipated a trend that continues, as automakers and suppliers develop ways to communicate directions, commands, safety measures and more to vehicles electronically.