1. Check that it is in auto answer mode. AT S0=1 in the init string sets the phone into auto answer mode. External modems have a AA LED that should be on.
    
2. Try with another cell phone, some phones will only answer calls from other cell phones
    
3. Check if there is a setting for the phone to be in data mode, some phones must manually be put in data mode.
    
4. Check that DTR is high, some modems will not answer the phone unless DTR is high.
   The command for the modem to ignore DTR is AT &D0.
   If the modem will answer the phone when connected to a PC this is most likely the problem.
   Most external modems have a TR LED, this needs to be ON.

[Home] [Trimble] [Basic Setup] [Phones] [Cables] [Troubleshooting] [Types] [US Carriers] [Internet Links]