Garmin 2620 Owners Manual - Page 26

Reference Driving with Dead Reckoning The only way you can tell that your StreetPilot is using Dead Reckoning is to view the GPS Information page. See page 56 for more information on GPS. Driving with Dead Reckoning (2660 Only) The StreetPilot 2660 comes with dead reckoning capabilities, which means that you continue to get navigation guidance even if you lose GPS reception, such as when you are travelling in dense urban environments with tall buildings and tunnels. To achieve dead reckoning, the 2660 utilizes an internal angular rate sensor, an external speed sensor input, and an external reverse light sensor input. A special dead reckoning cable is connected to your vehicle's speedometer and backup lights (it must be professionally installed by an authorized Garmin installer). Thus, when you lose GPS reception, your StreetPilot can acknowledge your turns as well as your distance travelled while you are driving. In this way, it can continue to accurately give navigation guidance until your GPS reception returns. Driving with dead reckoning capabilities is so seamless, you will not even know that you do not have GPS reception. You can simply unplug the dead reckoning cable from the vehicle adapter if you want to use the StreetPilot 2660 in another vehicle. It will navigate the same way as the StreetPilot 2620. 18