> 2.8.2 | Voice call handling – incoming calls

> This section comprises the subsections Description, Used AT Commands, Flow Chart, Hints and Example. To move to these subsections please use the Navigation Frame or the appropriate buttons on the toolbar.

> 2.8.2.1 | Description

> This chapter describes all AT commands you need to handle an incoming voice call.
> By default, an incoming call is indicated by the URC RING. With AT+CRC=1, the extended format of ring indication “+CRING: VOICE” can be enabled.
> A mobile terminated call can be answered with ATA or rejected with ATH or AT+CHUP. To hang up an existing call you can also use ATH or AT+CHUP. The result code “NO CARRIER” indicates that an existing call was disconnected or hung up by the other party. To check the reason of call release you can use the command AT+CEER.

> 2.8.2.2 | Used AT commands

> Command | Explanation
> ATA | Answer a call
> ATH | Disconnect existing connection
> AT+CHUP | Hang up call
> AT+CEER | Extended error report

> For further details about the commands see [2].

> 2.8.2.3 | Flow chart

> Figure 47: Voice call handling - incoming calls

> 2.8.2.4 | Hints

> Not applicable.

> 2.8.2.5 | Example

> Example 1:
> ***************************************
> Comment: Voice call handling - incoming call – reject
> ***************************************
> ***************************************
> Comment: Subscriber 2 makes a voice call to subscriber 1
> ***************************************
> Subscr 2 Send: ATD2400058;
> Subscr 2 Receive: ATD2400058;
> Subscr 1 Receive:
> Subscr 1 Receive: +CRING: VOICE
> ***************************************
> Comment: Subscriber 1 rejects the incoming voice call.
> ***************************************
> Subscr 1 Send: AT+CHUP
> Subscr 1 Receive: AT+CHUP
> Subscr 1 Receive: OK
> Subscr 2 Receive:
> Subscr 2 Receive: NO CARRIER
> Example 2:
> ***************************************
> Comment: Voice call handling - incoming call - answer call 1
> ***************************************
> ***************************************
> Comment: Subscriber 2 makes voice call to subscriber 1.
> ***************************************
> Subscr 2 Send: ATD2400058;
> Subscr 2 Receive: ATD2400058;
> Subscr 1 Receive:
> Subscr 1 Receive: +CRING: VOICE
> ***************************************
> Comment: Subscriber 1 answers the incoming voice call.
> ***************************************
> Subscr 1 Send: ATA
> Subscr 1 Receive: ATA
> Subscr 1 Receive: OK
> Subscr 2 Receive:
> Subscr 2 Receive: OK
> ***************************************
> Comment: Subscriber 2 hangs up the connection.
> ***************************************
> Subscr 2 Send: ATH
> Subscr 2 Receive: ATH
> Subscr 2 Receive: OK
> Subscr 1 Receive:
> Subscr 1 Receive: NO CARRIER
> ***************************************
> Comment: Subscriber 1 requests the cause of call release, in this case reason for NO CARRIER.
> ***************************************
> Subscr 1 Send: AT+CEER
> Subscr 1 Receive: AT+CEER
> Subscr 1 Receive: +CEER: 8,16,0
> Subscr 1 Receive:
> Subscr 1 Receive: OK
> Example 3:
> ***************************************
> Comment: Voice call handling - incoming call - answer call 2
> ***************************************
> ***************************************
> Comment: Subscriber 2 makes voice call to subscriber 1.
> ***************************************
> Subscr 2 Send: ATD2400058;
> Subscr 2 Receive: ATD2400058;
> Subscr 1 Receive:
> Subscr 1 Receive: +CRING: VOICE
> ***************************************
> Comment: Subscriber 1 answers the incoming voice call.
> ***************************************
> Subscr 1 Send: ATA
> Subscr 1 Receive: ATA
> Subscr 1 Receive: OK
> Subscr 2 Receive:
> Subscr 2 Receive: OK
> ***************************************
> Comment: Subscriber 1 hangs up the connection.
> ***************************************
> Subscr 1 Send: ATH
> Subscr 1 Receive: ATH
> Subscr 1 Receive: OK
> Subscr 2 Receive:
> Subscr 2 Receive: NO CARRIER