1) Check/set whether jumper of communication type switched correctly are per actully installed modem type: GPS or CDMA.

 2) Check communication status on display (Device Info) of the device. 

If cellular modem is not recognized in the device appropriate menu will not appear on the display.

In this case:

     - switch power off    

     - unplug the cellular modem card    

     - check all pins in the connector on the card. Are they not curved?   

     - check connector of the slot in the EM920

3) Plug the modem card into the slot.

4) Switch power up the EM920.

5) Input the APN exactly according by original description of appropricate cellular provider.

6)Try to disable pinging DNS serversby adding prefix #p before Access Point Name