Specifications
SIM900 AT Command Manual       
1 Circuit switched 
2  Packet Domain preferred (use circuit switched if 
GPRS not available) 
3 Circuit switched preferred (use Packet Domain if 
circuit switched not available) 
Reference 
Note 
The circuit switched service route is the default method 
SIM900_AT Command Manual_V1.03  168  12/24/2010 










