LG M4210LG Owner's Manual page 58

RS-232C
Transmission / Receiving Protocol
33. Auto volume (Command : d u)
Automatically adjust the volume level.
Transmission
[d][u][][Set ID][][Data][x]
Data 0 : Off
1 : On
Acknowledgement
[u][][Set ID][][OK/NG][Data][x]
34. Speaker (Command : d v)
Turn the speaker on or off.
Transmission
[d][v][][Set ID][][Data][x]
Data 0 : Off
1 : On
Acknowledgement
[v][][Set ID][][OK/NG][Data][x]
Controlling the Multiple Product
A20