Specifications

SIM900 AT Command Manual
SIM900_AT Command Manual_V1.03 227 12/24/2010
point name and IP address aren’t set.
Cancel a context using the terminal
equipment
Pause data transfer and enter Command
mode by +++
Stop the GPRS data transfer
AT+CGDCONT=1,
"IP","CMNET"
ATD*99#
+++
ATH
OK
CONNECT
OK
OK
Reconnect a context using the terminal
equipment
Resume the data transfer
AT+CGDCONT=1,
"IP","CMNET"
ATD*99#
+++
ATO
OK
CONNECT
OK
CONNECT
*Quality of Service (QOS) is a special parameter of a CID which consists of several parameters itself.
The QOS consists of
The precedence class
The delay class
The reliability class
The peak throughput class
The mean throughput class
And is decided in "requested QOS” and "minimum acceptable QOS”.
All parameters of the QOS are initiated by default to the "network subscribed value (=0)" but the
QOS itself is set to be undefined. To define a QOS use the AT+CGQREQ or AT+CGQMIN
Command.
Overwrite the precedence class of
QOS of CID 1 and sets the QOS of
CID 1 to be present
AT+CGQREQ=1,2 OK
Response: all QOS values of CID 1
are set to network subscribed except
precedence class which is set
to 2
AT+CGQREQ +CGQREQ:1,2,,,,
+CGQREQ: 3,0,0,3,0,0
OK
Set the QOS of CID 1 to not present.
Once defined, the CID can be activated.
AT+CGQREQ=1 OK
Activate CID 1, if the CID is already
active, the mobile returns OK at once.
If no CID is defined the mobile responds
+CME ERROR: invalid index.
Note: If the mobile is NOT attached
by AT+CGATT=1 before activating, the
AT+CGACT=1,1
AT+CGACT=1,3
OK
+CME ERROR: requested
service option not
subscribed.