For BC95-G

1. Check the reason why you can't access the network:

1) AT+CEREG=5

2) AT+CEREG?       //   This process may be longer, please repeat the input

3) Mainly check the two parameters cause_type and reject_case

2. Network access operation:

1) AT+CFUN=0

2) AT+NBAND=X                 //  X means the local frequency band number

3) AT+NRB

4) After waiting for a period of time, you can use AT+CSQ to query the network access

Remarks:

1. The operating voltage of the SIM card used must be less than 3.0V.

2. The network access time varies with the signal strength.

3. If you have not been able to access the network, please try to access the network manually.

3. Check the PS Attach or Detach  

1) AT+CGATT?

Response
+CGATT: <state>
OK

Write Command
AT+CGATT=<state>

<state> Integer type. Indicates the state of PS attachment.
0 Detached
1 Attached
 

Note:Generally, when registering with an operator, attaching GPRS is automatic, and CGATT can manually attach the network.

4. Check the signaling connection status:

1) AT+CSCON?

Response
+CSCON: <n>,<mode>
OK

<n> Enable/disable the URC. 
0 Disable the URC
1 Enable URC +CSCON: <mode> 
<mode>Signaling connection status.
0 Idle
1 Connected

5. Check the PDP Context Activate/Deactivate

1) AT+CGACT?

Response
[+CGACT: <cid>,<state>]

[+CGACT: <cid>,<state>]
[…]
OK

<state> Integer type. The state of PDP context activation.
0 Deactivated
1 Activated
<cid> Integer type. A numeric parameter which specifies a particular PDP context definition (see 
AT+CGDCONT).
 

Note:Note that having a cell ID attached to the network does not necessarily mean successful activation. For data exchange, such as initiating HTTP requests, activation is necessary to use them.