> 6.1 | Supported Audio Modes

> Table 4 contains a summary of the audio modes supported by Siemens GSM modules. Further details are explained in [1] and [2]. The audio mode can be selected with the AT^SNFS command. You have the choice of six audio modes selectable with AT^SNFS. By default, each audio mode is assigned to one of the two interfaces: audio modes 1, 4 and 5 are allocated to the 1st interface, and audio modes 2, 3 and 6 to the 2nd interface.
> If this default assignment fits the design of the host application, the AT^SNFS command is sufficient to select an audio mode and activate the interface automatically assigned to this mode.

> Table 4: | Selectable audio modes

> No. | Name | AT command | Purpose | Description of mode and interface assigned by default
> 1 | Default Handset | AT^SNFS=1 | Approval configuration of module | MIC1, EP1, adapted to Votronic Handset HH-SI-30.3 with DSB75 Support Board, not adjustable. Default: Audio interface 1 (MIC1, EP1).
> 2 | Basic Speakerphone | AT^SNFS=2 |  | MIC2, EP2, adapted to Siemens CarKit Portable, 5 volume steps selectable. Default: Audio interface 2 (MIC2, EP2).
> 3 | Headset | AT^SNFS=3 |  | MIC2, EP2, adapted to standard Mono-Headsets, 5 volume steps selectable. Default: Audio interface 2 (MIC2, EP2).
> 4 | User Handset | AT^SNFS=4 | Approval configuration of customer application | MIC1, EP1, Votronic Handset HH-SI-30.3 with DSB75 Support Board, 5 volume steps selectable. Default: Audio interface 1 (MIC1, EP1).
> 5 | Plain Codec | AT^SNFS=5 |  | MIC1, EP1, no filtering, 5 volume steps selectable. Default: Audio interface 1 (MIC1, EP1).
> 6 | Plain Codec | AT^SNFS=6 |  | MIC2, EP2, no filtering, 5 volume steps selectable. Default: Audio interface 2 (MIC2, EP2)

> When shipped from factory, Siemens GSM modules are set to interface 1 and audio mode 1. This configuration is optimized for the Votronic HH-SI-30.3/V1.1/0 handset and used for type approving the Siemens reference equipment. Audio mode 1 has fix parameters which cannot be altered. To adjust the settings of the Votronic handset simply select another audio mode.
> If an audio interface is operated with audio modes other than those assumed by default, the AT^SAIC command can be used in addition to AT^SNFS. AT^SAIC (see Section 6.2) selects the analog interface and changes the microphone (MIC1 or MIC2) and speaker (EP1 or EP2) activated by default. So, using both AT commands increases the combinations of audio interfaces and audio modes, giving greater flexibility to connect different devices.