Silicon Laboratories SI2494/39 manual Handset to TAM Hands-Free Transition, Terminate, AT+VLS=14

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