GSM Module
2.1.25
+CHLD: call hold
Description
This command is used to set call held and conference call.
Format
AT+CHLD=[<n>]
AT+CHLD=?
Check supported <n>
+CHLD: (list of supported <n>s )
OK
Example
AT+CHLD=[<n>]
Set call held and conference call;
If the setting is successful:
OK
If there is an error in operation:
+CME ERROR: <err>
Parameters
<n>
0: release all held calls or set a waiting call as UDUB
1: Release all activated calls and receive a held or waiting call.
1X: Release call X
2: Hold all activated calls and receive another held or waiting call.
2X: hold all calls except for call X
3: Add the held call into the conference call
Remarks
1.
This command is used for telecom service;
2.
The range of X value:1~7
3.
When there is both held call and waiting call, the process above
should be applied for the waiting call.
4.
When releasing call, please firstly use AT+CHLD=1 to release the
current call, and use ATH to hang up the call.
5.
Please refer to the method of conference call provided by the
operator when using AT+CHLD=3.
2.1.26
*TSIMINS: check SIM card status
Description
This command is used to check SIM card status.
Format AT*TSIMINS=num,
status
Example AT*TSIMINS?
*TSIMINS:0,0
OK
Check SIM card status.
No SIM card.
Parameters
Num: take 0 or 1, no meaning.
Status
：
0
：
There is no SIM card;
1
：
There is SIM card.
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