Silicon Laboratories SI2493/57/34/15/04 - Manual (Page 199)

AN93
Rev. 1.3 199
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
Commands / Data
Modem to Host Result
Codes/Data
Local Modem Actions
AT:U199|A 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.
AT:U72,0108 OK
Configure Si3000 Register 1:
Disable speaker driver
Enable line output driver
Disable telephone instrument driver
Disable MBIAS output
AT:U72,05D7 OK
Configure Si3000 Register 5:
20 dB Line In gain
Enable Line In
20 dB MIC input gain
Mute MIC input
Mute telephone instrument input
Enable IIR filter
AT:U72,065E OK
Configure Si3000 Register 6:
0 dB RX PGA gain
Enable Line Out
Disable telephone instrument output
AT:U72,075E OK
Configure Si3000 Register 7:
0 dB RX PGA gain
Enable SPKRL
Mute SPKRR
AT:U72,0900 OK
Configure Si3000 Register 9:
0 dB Line Out attenuation
0 dB Speaker output attenuation
AT:U199&FFF7 OK Enable speaker for local ring tone/alert tones.