Voice Call- AT commands to set up voice call

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With Online AT Command Tester tool, you can test outgoing and incoming voice calls. The tool provides easy to use interface to dial outgoing number and accept incoming calls.

The AT Command Tool will first check whether the device is registered on the network. If so, it will send the necessary AT commands to initiate teh voice call. For incoming calls, it will monitor the device for “RING” command and alert the user.

Once the device us powered up, check whether SIM card is present. If the SIM is not inserted properly or if the SIM card is locked, please correct those issues.
AT+CPIN?
+CPIN: READY
OK
The device above returns that the SIM is ready to use.

Then check the registration status of the device.
If the regisration status is “Searching” or “Not Registered”, that means that the device is not able to acquire the signal from the base station. The device should usually find the nearest base station within few minutes (max 15min). If you dont get “Registered” response for the AT+CGREG command,
- Verify that the antenna is properly connected on the device
- Verify that the bands supported by the device match the bands of the network provider

AT+CGREG?
+CGREG: 0,1
OK
In the above case, the device returns that it is registred in the home network.

After verifying the network registration status, you can get the network information. If the device is registered on the home network, the network info on the SIM card used should match the network info returned by the AT+COPS command,
AT+COPS?
+COPS: 0,0,”T-Mobile”
OK

Now check the signal quality.
AT+CSQ
+CSQ: 10,0
OK
That return corresponds to a RSSI value of -93 dBm. This is only slightly better than marginal coverage. We should still be able to make a call on this signal condition, but the throughput may not be that good.

Now dial the number,
ATD858#######;
OK

Once the called number is answered, the device should establish a voice call.
To hangup the call, send the hang-up AT command.
ATH

The voice call will be ended after the hang-up command is sent. The device will be go back to monitoring the network state.

To call the last dialled number again,
ATDL
OK

Answer voice call using AT command
To answer an incoming call, mobile device should send the ATA response. To verify this, you can connect appropriate port of the device to the Hyperterminal program. Find out the phone number of the device,

AT+CNUM
+CNUM: “Line 1?,”+1858#######?,145
OK

Call the above phone number using another landline phone or mobile phone. The hyperterminal should indicate the incoming call through the ‘RING’ alert. Answer the phone call by issuing the ATA command in the hyperterminal.

RING

RING
ata
OK

You can configure the device to automatically answer the call through AT command,
ATS0=1
OK
Above configuration will auto-anser after 1 ring. To disable auto-answering,
ATS0=0
OK

Keywords: Module voice call, M2M voice call, GPRS voice call, 3G voice call, voice call through AT commands,