> 2.8.3 | Voice call handling – outgoing 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.

> 2.8.3.1 | Description

> To make a mobile originated voice call use the commands ATD, ATD>mem, ATD>n, ATD>str, ATDL or ATDI. Remember that for voice calls the semicolon “;” must be appended after the destination number. Otherwise the call would be interpreted as a CSD call.
> When dialing with one of the ATD commands the following responses can be returned:
> OK
> NO CARRIER
> BUSY
> NO DIALTONE
> Call barred
> To hang up a call the command ATH or AT+CHUP can be used either by the caller or by the called party. The result code “NO CARRIER” indicates that an existing call was disconnected or hung up by the other party.
> No matter whether the call attempt was successful or not you can use the command AT+CEER to request the cause of call release.

> 2.8.3.2 | Used AT commands

> Command | Explanation
> ATD | Mobile originated call to dial a number
> AT+CEER | Extended error report
> ATH | Disconnect existing connection
> AT+CHUP | Hang up call

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

> 2.8.3.3 | Flow chart

> Figure 48: Voice call handling - outgoing calls

> 2.8.3.4 | Hints

> • | If a maximum number of dial retries to the same destination fails in a row, the dialed number is blacklisted according to “GSM02.07 Annex A“. In this case dialing will be denied until the number is cleared from the blacklist. Possible responses are “Call barred” for voice call numbers, and “NO CARRIER” for fax or data numbers. For further details refer to the description of ATD in [2].

> • | The minimum time between call attempts is described in [11], may differ depending on the used provider.

> 2.8.3.5 | Example

> Example 1:
> ***************************************
> Comment: Voice call handling - outgoing call 1
> ***************************************
> ***************************************
> Comment: Subscriber 1 makes voice call to subscriber 2.
> ***************************************
> Subscr 1 Send: ATD2400058;
> Subscr 1 Receive: ATD2400058;
> Subscr 2 Receive:
> Subscr 2 Receive: +CRING: VOICE
> ***************************************
> Comment: Subscriber 2 rejects the incoming voice call.
> ***************************************
> 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: 8,21,0
> Subscr 1 Receive:
> Subscr 1 Receive: OK
> Example 2:
> ***************************************
> Comment: Voice call handling - outgoing call 2
> ***************************************
> ***************************************
> Comment: Subscriber 1 makes voice call to subscriber 2.
> ***************************************
> Subscr 1 Send: ATD2400058;
> Subscr 1 Receive: ATD2400058;
> Subscr 2 Receive:
> Subscr 2 Receive: +CRING: VOICE
> ***************************************
> Comment: Subscriber 2 answers the incoming voice call.
> ***************************************
> Subscr 2 Send: ATA
> Subscr 2 Receive: ATA
> Subscr 2 Receive: OK
> Subscr 1 Receive:
> Subscr 1 Receive: OK
> ***************************************
> Comment: Subscriber 1 hangs up the call.
> ***************************************
> Subscr 1 Send: ATH
> Subscr 1 Receive: ATH
> Subscr 1 Receive: OK
> Subscr 2 Receive:
> Subscr 2 Receive: NO CARRIER