7.6.2.1. Record OGM. Silicon Laboratories Si2493, Si2404, Si2415, Si2434, Si2494, Si2439, Si2457, Si2443

AN93

7.6.2.1. Record OGM

The Si3000-to-RS232 gain register UC0 in the ISOmodem can be used to adjust the voice stream gain. Use the

+VGR command to adjust the UC0 value in command mode. It is best to maintain two versions of +VGR: one for

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

Table 141. TAM Hands-Free Record OGM

Host to Modem Commands /

Data

Modem to Host Result

Codes/Data

Local Modem Actions

AT+VGR=128

AT:U0B1,0500

AT+VSD=129

AT+VSM=4

AT+VTS=[1000,0,100]

AT:U199|8

AT:U199&FFFD

AT+VRX

<DLE><!>

AT:U0B1,0

AT:U199|2

AT:U199&FFF7

OK

OK

OK

OK

OK

OK

OK

CONNECT

[Voice Stream]

<DLE><ETX>

OK

OK

OK

OK

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 to avoid echo (speakerphone algorithm off).

Enable microphone for OGM recording.

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.

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.

Disable Si3000-to-DAA transmit gain path. This ensures codec tones are not sent to the FDV and

DTMF.

Mute the microphone.

Enable speaker for local ring tone/alert tones.

Rev. 1.41

215