> 2.8.1 | Voice call handling initialization

> 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.

> 2.8.1.1 | Description

> This chapter describes basic settings recommended to handle mobile originated and mobile terminated voice calls:

> • | The command AT+CSNS enables the ME to accept incoming calls when no bearer capability information is provided with the call. The setting must be set before the call is received. For voice calls the default setting AT+CSNS=0 can be kept.

> • | The AT^SM20 command specifies two call setup response modes, i.e. two different modes of responses returned when dialing voice call numbers with ATD: AT^SM20=1 (factory default) causes the ME to respond once the call setup is completed either successfully (“OK”) or unsuccessfully (“NO CARRIER”, “NO DIAL TONE”, “BUSY”). AT^SM20=0 causes the ME to return “OK” immediately after dialing was completed (i.e. before call setup terminates successfully or unsuccessfully).

> • | The ATX command specifies different result code formats and enables / disables the presentation of dial tones and busy signals during call setup. The setting can be stored to the user profile using AT&W.

> • | Use AT+CRC to enable or disable the extended format of result codes for incoming call indication. In the case of voice calls AT+CRC=1 can be used to replace the factory default result code “RING” with the extended format “+CRING VOICE”.

> • | Depending on the type of Siemens module, autoanswer mode (ATS0≠000) is also supported for voice calls. If supported, this is explicitly stated in [2], chapter ATS0.

> 2.8.1.2 | Used AT commands

> Command | Explanation
> AT+CSNS | Single numbering scheme
> AT^SM20 | Set M20 Compatibility
> ATX | Set CONNECT result code format and call monitoring
> AT&W | Store current configuration to user defined profile
> ATS0 | Set number of rings before automatically answering the call (not supported by all products)

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

> 2.8.1.3 | Flow chart

> Figure 46: Voice call handling initialization

> 2.8.1.4 | Hints

> • Out of the AT commands listed in this chapter only ATX can be stored with AT&W.

> 2.8.1.5 | Example

> ***************************************
> Comment: Voice call handling intialization
> ***************************************
> ***************************************
> Comment: Set single numbering scheme to receive all calls without bearer elements as voice calls.
> ***************************************
> Subscr 1 Send: AT+CSNS=0
> Subscr 1 Receive: AT+CSNS=0
> Subscr 1 Receive: OK
> ***************************************
> Comment: Set compatibility to SM20.
> ***************************************
> Subscr 1 Send: AT^SM20=1,1
> Subscr 1 Receive: AT^SM20=1,1
> Subscr 1 Receive: OK
> ***************************************
> Comment: Enable dial tone and busy detection.
> ***************************************
> Subscr 1 Send: ATX4
> Subscr 1 Receive: ATX4
> Subscr 1 Receive: OK
> ***************************************
> Comment: Enable automatic answer after 3 rings (Autoanswer mode for voice calls
> is not supported by all products)
> ***************************************
> Subscr 1 Send: ATS0=003
> Subscr 1 Receive: ATS0=003
> Subscr 1 Receive: OK
> ***************************************
> Comment: Store settings to user profile.
> ***************************************
> Subscr 1 Send: AT&W
> Subscr 1 Receive: AT&W
> Subscr 1 Receive: OK