SIM900 (AT+SAPBR=3,1,“CONTYPE”,“GPRS“) returns ”ERROR"

Hardware Arduino GSM Shield
1

I am using SIM900 GSM module which connected with Arduino MEGA 2560. When I send the following command (AT+SAPBR=3,1,“CONTYPE”,“GPRS”) to set up connection type of GPRS, I got response “ERROR”.

Command sequences that I send are here:

**Commands are here**         **Responses are here**

// See if the SIM900 is ready
AT                                  OK

// SIM card inserted and unlocked?
AT+CPIN?                            +CPIN: READY
                                    OK

// Is the SIM card registered?
AT+CREG?                            +CREG: 0,1
                                    OK

// Is GPRS attached?
AT+CGATT?                           +CGATT: 1
                                    OK

// Check signal strength - should be 9 or higher
AT+CSQ                              +CSQ: 14,0
                                    OK

// Set connection type to GPRS
AT+SAPBR=3,1,"Contype","GPRS"       ERROR

Could you please help to understand what is the issue? Note that I checked SMS and RING and that works fine. the problem is only related to the mentioned command.

Thanks,
Vladimir

2

i solved this by deleting (") s in the line like and writing contype and gprs in capital letters. you can send this via terminal

AT+SAPBR=3,1,CONTYPE,GPRS