Silicon Laboratories SI2493/57/34/15/04 - Manual (Page 202)

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202 Rev. 1.3
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 127. TAM Hands-Free Record OGM
Host to Modem Commands /
Data
Modem to Host Result
Codes/Data
Local Modem Actions
AT+VGR=128 OK
Set the Si3000-to-RS232 receive gain (UC0) for TAM
Hands-Free.
AT:U0B1,0500 OK
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.
AT+VSD=129 OK
Set sensitivity level for OGM recording silence detec-
tion.
AT+VSM=4 OK
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.
AT+VTS=[1000,0,100] OK Play user record tone prompt.
AT:U199|8 OK
Mute speaker to avoid echo (speakerphone algorithm
off).
AT:U199&FFFD OK Enable microphone for OGM recording.
AT+VRX CONNECT
Trigger receive operation. The first byte after the new-
line character following the CONNECT message will be
the first data stream byte.
[Voice Stream]
Receive OGM voice stream. During voice stream cap-
ture, the user can adjust the UC0 value via the
and commands. The host voice
driver will need track the number of adjustments and
update the +VGR value for future use.
OK
Terminate the receive operation. The modem will
respond with to mark the end of the data
stream. The OK denotes the return to command mode.
AT:U0B1,0 OK
Disable Si3000-to-DAA transmit gain path. This
ensures codec tones are not sent to the FDV and
DTMF.
AT:U199|2 OK Mute the microphone.
AT:U199&FFF7 OK Enable speaker for local ring tone/alert tones.