Multitech MT2834ZDX - Command Group: V.42 Mode and Speaker Control; V.42 Mode Selection; Modem Speaker Control

4 AT Commands, S-Registers, and Result Codes
45
L10 List signal to noise ratio information (SNR).
L11 List noise information.
Note: For L9, L10, and L11, you must first type +++AT<CR> (on-line
escape command while maintaining command mode), then type the
command prefixed by an AT (e.g., ATL10).
Command: #L n V.42 Mode Selection in Originate Mode
Values: n = 0, 1, 2, or 3
Default: 0
Description: #L0 Modems negotiate V.42 mode.
#L1 MNP on & LAP-M off.
#L2 LAP-M on & MNP off.
#L3 Disable detection phase and go directly to LAP-M.
Command: M n Modem Speaker Control
Values: n = 0, 1, 2, or 3
Default: 1
Description: M0 Speaker always off.
M1 Speaker on until carrier signal detected.
M2 Speaker always on.
M3 Speaker on during dialing, off during handshaking.