Modem not responding

Hi All,

if i gave wvdial command on terminal i am getting below error.

/ # wvdial                                                                      
--> WvDial: Internet dialer version 1.60                                        
--> Initializing modem.                                                         
--> Sending: ATZ                                                                
OK                                                                              
--> Sending: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0                                  
ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0                                               
OK                                                                              
--> Sending: AT+CGDCONT = 1, "IP", "airtelgprs.com"                             
AT+CGDCONT = 1, "IP", "airtelgprs.com"                                          
OK                                                                              
--> Sending: ATD                                                                
ATD                                                                             
NO CARRIER                                                                      
--> Sending: ATQ0                                                               
ATQ0                                                                            
OK                                                                              
--> Re-Sending: ATD                                                             
ATD                                                                             
NO CARRIER                                                                      
--> Modem not responding.                                                       
/ #

pls help

raghava