7.6.2.2. Review OGM. Silicon Laboratories Si2493, Si2404, Si2415, Si2434, Si2494, Si2439, Si2457, Si2443

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7.6.2.2. Review OGM

The RS232-to-Si3000 gain register UB8 in the ISOmodem can be used to adjust the voice stream gain. Use the

+VGT command to adjust the UB8 value in command mode. It is best to maintain two versions of +VGT: one for

RS232-to-Si3000 and another for RS232-to-DAA.

Table 142. TAM Hands-Free Review OGM

Host to Modem Commands

/ Data

Modem to Host Result

Codes/Data

Local Modem Actions

AT+VGT=128

AT+VSM=4

AT+VTX

[Voice Stream]

<DLE><ETX>

OK

OK

CONNECT

<DLE><u>

OK

Set the RS232-to-Si3000 transmit gain (UB8) for TAM

Hands-Free.

Select G.711U

-law PCM, 8-bit, 64 kbps format. The voice driver will need to track the OGM format with the

OGM PCM file.

Trigger transmit operation.

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 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.

Terminate the transmit operation. The modem will respond with OK to denote the return to command mode.

7.6.2.3. Record Local ICM

The Record Local ICM is identical to the Record OGM procedure provided in Table 141 on page 215. The main

difference is that one of the ADPCM formats is generally used and the PCM file is stored with the other ICM files recorded from the PSTN.

7.6.2.4. Review ICM

The Review ICM is identical to the Review OGM procedure provided in Table 142 on page 216. The main

difference is that one of the ADPCM formats is generally used to conserve message space.

7.6.2.5. Speakerphone Transition

The SP Button On Event will trigger this transition. See Table 149 on page 231 for configuration sequence.

7.6.2.6. Handset Transition

The Handset Raised Event will trigger this transition. See Table 134 on page 210 for configuration sequence.

7.6.3. TAM Handset

Using the handset to record the OGM will result in better message quality. The handset can also be used to screen messages in private. The host will need to correctly process the Handset Raised Event to keep the modem onhook during record/review operations.

7.6.3.1. Record OGM

The host will prompt the user to lift the handset to begin OGM recording. The procedure restores the TAM Hands-

Free settings before completion.

216 Rev. 1.41

AN93

Table 143. TAM Handset Record OGM

Host to Modem Commands / Data

Modem to

Host Result

Codes/Data

Local Modem Actions

AT:U199|A

AT:U72,0110

AT:U72,05B3

AT:U72,065C

AT:U72,075E

AT:U72,0900

AT+VGR=128

AT:U0B1,0500

AT+VSD = 129

AT+VSM = 4

AT+VTS = [1000,0,100]

AT:U199|8

AT:U199&FFFD

OK

OK

OK

OK

OK

OK

OK

OK

OK

OK

OK

OK

OK

Mute the microphone and speaker paths to the codec.

Configure Si3000 Register 1:

Enable speaker driver

Disable line output driver

Disable telephone instrument driver

Enable MBIAS output

Configure Si3000 Register 5:

10 dB Line In gain

Mute Line In

20 dB MIC input gain

Enable MIC input

Mute telephone instrument input

Enable IIR filter

Configure Si3000 Register 6:

0 dB RX PGA gain

Disable Line Out

Disable telephone instrument output

Configure Si3000 Register 7:

0 dB RX PGA gain

Enable SPKRL

Mute SPKRR

Configure Si3000 Register 9:

0 dB Line Out attenuation

0 dB Speaker output attenuation

Set the Si3000-to-RS232 receive gain

(UC0) for TAM Hands-Free.

Restore Si3000-to-DAA transmit gain path to allow voice samples to reach FDV block for silence detection. This allows the driver to automatically end OGM recording.

Set sensitivity level for OGM recording silence detection.

Select G.711U

-law PCM, 8-bit, 64 kbps format. The voice driver will need to track the OGM format with the OGM PCM file.

Play user record tone prompt.

Mute speaker.

Enable microphone for OGM recording.

Rev. 1.41

217

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Table 143. TAM Handset Record OGM (Continued)

AT+VRX

<DLE><!>

AT:U0B1,0

AT:U199|A

AT:U72,0108

AT:U72,05D7

AT:U72,065E

AT:U72,075E

CONNECT

[Voice Stream]

Trigger receive operation. The first byte after the newline character following the

CONNECT message will be the first data stream byte.

Receive OGM voice stream. During voice stream capture, the user can adjust the

UC0 value via the <DLE><u> and

<DLE><d> commands. The host voice driver will need track the number of adjustments and update the +VGR value for future use.

<DLE><ETX>

OK

OK

Terminate the receive operation. The modem will respond with <DLE><ETX> to mark the end of the data stream. The OK denotes the return to command mode. A

Handset Lowered Event, timeout, or silence event can trigger the <DLE><!> transmission.

Disable Si3000-to-DAA transmit gain path.

This ensures codec tones are not sent to the FDV and DTMF.

OK

OK

OK

OK

OK

Mute the microphone and speaker paths to the codec.

Configure Si3000 Register 1:

Disable speaker driver

Enable line output driver

Disable telephone instrument driver

Disable MBIAS output

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

Configure Si3000 Register 6:

0 dB RX PGA gain

Enable Line Out

Disable telephone instrument output

Configure Si3000 Register 7:

0 dB RX PGA gain

Enable SPKRL

Mute SPKRR

218 Rev. 1.41