Longshine LCS-8056C2 - Manual (Page 156)

Commands for Host-Processed Modems Reference Manual
5-24 Conexant 100498E
+VGM - Microphone Gain
This command causes the modem to set the microphone gain of the speakerphone function.
Syntax
+VGM=
Defined Values
Decimal number between 0 and 255 corresponding to the gain.
Reporting Current or Selected Values
Command: +VGM?
Response: +VGM:
Example: +VGM: 130 For the default setting.
Reporting Supported Range of Parameter Values
Command: +VGM=?
Response: +VGM: range
Example: +VGM: 0-255
Result Codes
OK = 0-255.
ERROR Otherwise, or if not in Voice Mode with speakerphone enabled
(+VSP=1).