Telebit T3000 Reference Manual page 83

L(n) Speaker Volume
Range: 0-3
Default: 2
The L command determines the speaker volume.
L Same as LO.
LO Low volume.
L 1 Low volume.
L2 Medium volume.
L3 High volume.
M(n) Speaker Mode
Range: 0-3
Default: 1
The M command controls the modem's internal
speaker.
M Same as MO.
MO Speaker disabled.
M1 Speaker enabled only when dialing and
connecting.
M2 Speaker enabled at all times.
M3 Speaker enabled after dialing until carrier
detected.
O(n) Return to Data State
Range: 0-1
The 0 command places the modem in a data state
during a connection. When the modem has been
forced to enter command mode with the break signal
or the escape sequence, the 0 command resumes data
5-8 AT Command Descriptions