AN93

7.5.7. Terminate

Upon detection of the Handset Lowered Event, the host should issue the commands in Table 124 to transition to the TAM Hands-Free mode.

Table 124. Handset to TAM Hands-Free Transition

Host to Modem

Modem to Host Result

Local Modem Actions

Commands / Data

Codes/Data

 

 

 

 

AT:U199A

OK

Mute the microphone and speaker paths to the codec.

 

 

 

AT+VSP=0

OK

Select handset voice path. See Figure 29 on page 188 for details.

+VSP must be zero when exiting from +VLS=13.

 

 

 

 

 

AT+VLS=0

OK

Disable voice mode. Used as a transition point between

non-zero +VLS voice modes.

 

 

 

 

 

AT+VLS=14

OK

Setup on-hook voice mode. See Table 117 on page 190 for

details. This will return the modem to on-hook state.

 

 

 

 

 

AT:U0B1,0

OK

Disable Si3000-to-DAA transmit gain path. This ensures

codec tones are not sent to the FDV and DTMF.

 

 

 

 

 

AT:U0B5,0

OK

Disable DAA-to-Si3000 receive gain path. This ensures line

events such as CID and ring are not heard via the codec.

 

 

 

 

 

 

 

Configure Si3000 Register 1:

 

 

Disable speaker driver

AT:U72,0108

OK

Enable line output driver

 

 

Disable telephone instrument driver

 

 

Disable MBIAS output

 

 

 

 

 

Configure Si3000 Register 5:

 

 

20 dB Line In gain

 

 

Enable Line In

AT:U72,05D7

OK

20 dB MIC input gain

 

 

Mute MIC input

 

 

Mute telephone instrument input

 

 

Enable IIR filter

 

 

 

 

 

Configure Si3000 Register 6:

AT:U72,065E

OK

0 dB RX PGA gain

Enable Line Out

 

 

 

 

Disable telephone instrument output

 

 

 

 

 

Configure Si3000 Register 7:

AT:U72,075E

OK

0 dB RX PGA gain

Enable SPKRL

 

 

 

 

Mute SPKRR

 

 

 

 

 

Configure Si3000 Register 9:

AT:U72,0900

OK

0 dB Line Out attenuation

 

 

0 dB Speaker output attenuation

 

 

 

AT:U199&FFF7

OK

Enable speaker for local ring tone/alert tones.

 

 

 

Rev. 1.3

199

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Image 199
Silicon Laboratories SI2494/39, SI2493/57/34/15/04 manual Handset to TAM Hands-Free Transition, Terminate, AT+VLS=14