During the NL2 installation, a user calibration is recommended.
The NL2 is sent from the factory with jumper wires inserted in its
GPS Receiver (PS2) port. These wires will assist with the
Calibration procedure; remove them once the process is done.

For complete instructions refer to the relevant
                      Nlx Install and Operation Guide


These video clips demonstrate the complete procedure; they’re
a visual aid only... There’s no sound track. Please review the
Installation Guide first.

http://www.youtube.com/watch?v=xh1nG10i7X0