> 5.7.3 | Characteristics of Audio Modes

> The electrical characteristics of the voiceband part depend on the current audio mode set with the AT^SNFS command. All values are noted for default gains e.g. all parameters of AT^SNFI and AT^SNFO are left unchanged.

> Table 35: | Voiceband characteristics (typical)

> Audio mode no. AT^SNFS= | 1 (Default settings, not adjustable) | 2 | 3 | 4 | 5 | 6
> Name | Default Handset | Basic Handsfree | Headset | User Handset | Plain Codec 1 | Plain Codec 2
> Purpose | DSB with Votronic handset | Car Kit | Siemens Headset | DSB with individual handset | Direct access to speech coder | Direct access to speech coder
> Gain setting via AT command. Defaults: inBbcGain outBbcGain | Fix 5 (30dB) 1 (-6dB) | Adjustable 2 (12dB) 2 (-12dB) | Adjustable 5 (30dB) 1 (-6dB) | Adjustable 5 (30dB) 1 (-6dB) | Adjustable 0 (0dB) 0 (0dB) | Adjustable 0 (0dB) 0 (0dB)
> Default audio interface | 1 | 2 | 2 | 1 | 1 | 2
> Power supply VMIC | ON | ON | ON | ON | ON | ON
> Sidetone | Fix | --- | Adjustable | Adjustable | Adjustable | Adjustable
> Volume control | Fix | Adjustable | Adjustable | Adjustable | Adjustable | Adjustable
> Echo canceller | ON | ON | ON | ON | OFF | OFF
> Noise reduction | 6dB | 12dB | 12dB | 6dB | OFF | OFF
> MIC input signal for 0dBm0 1 -10dBm0 f=1024 Hz | 16mV 5mV | ---2 90mV | 18mV 16mV | 16mV 5mV | 400mV 126mV | 400mV 126mV
> EP output signal in mV rms. @ 0dBm0, 1024 Hz, no load (default gain) / @ 3.14 dBm0 | 660mV | 240mV default @ max volume | 740mV default @ max volume | 660mV default @ max volume | 1.47V Vpp = 6.2V | 1.47V Vpp = 4.2V3
> Sidetone gain at default settings | 21dB | - dB | 10.0dB | 21dB | - dB | - dB

> 1
> All values measured before the noise reduction attenuates the sine wave after a few seconds.
> 2
> 0dBm0 cannot be achieved at 1024Hz due to attenuation of the frequency correction filter for the sending direction at this frequency.
> 3
> Output voltage is limited to 4.2V.
> Note: With regard to acoustic shock, the cellular application must be designed to avoid sending false AT commands that might increase amplification, e.g. for a highly sensitive earpiece. A protection circuit should be implemented in the cellular application.