Silicon Laboratories SI2494/39, SI2493/57/34/15/04 manual AT+VSM=4, AT+VTX Connect

		AN93
Table 130. TAM Handset Review OGM (Continued)
AT+VSM=4	OK	Select G.711U μ-law PCM, 8-bit, 64 kbps
		format. The voice driver will need to track
		the OGM format with the OGM PCM file.
AT+VTX	CONNECT	Trigger transmit operation.
	<DLE><u>	TX Underrun. Appears at the start of +VTX
		before transmit data are seen.
		Transmit OGM voice stream. During voice
		stream capture, the user can adjust the UB8
[Voice Stream]		value via the <DLE><u> and <DLE><d>
		commands. The host voice driver will need
		track the number of adjustments and update
		the +VGT value for future use.
<DLE><ETX>	OK	Terminate the transmit operation. The
		modem will respond with OK to denote the
		return to command mode.
AT:U199A	OK	Mute the microphone and speaker paths to
		the codec.
		Configure Si3000 Register 1:
AT:U72,0108	OK	Disable speaker driver
		Enable line output driver
		Disable telephone instrument driver
		Disable MBIAS output
		Configure Si3000 Register 5:
		20 dB Line In gain
AT:U72,05D7	OK	Enable Line In
		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
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.

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