4 at commands, s-registers, and result codes, Multimodemii user guide – Multitech MULTI MODEM II MT5600BA User Manual
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4 AT Commands, S-Registers, and Result Codes
41
MultiModemII User Guide
Command:
%C
n Data Compression Control
Values:
n = 0, 1, 2, or 3
Default:
3
Description:
Enables or disables data compression negotiation. The modem
can only perform data compression on an error-corrected link.
%C0 Disables data compression.
%C1 Enables MNP 5 data compression negotiation.
%C2 Enables V.42bis data compression negotiation.
%C3 Enables both V.42bis and MNP 5 data compression negotiation.
Note:
This command controls both V.42bis and MNP-5 data
compression, whereas the &E14 and &E15 commands control
only V.42bis data compression. The command in effect is the
one last entered.
Command:
%E
n Line Quality Monitor
Values:
n = 0, 1, or 2
Default:
2
Description:
Controls whether or not the modem will automatically moni-
tor the line quality and request a retrain (%E1) or fall back to a
lower speed when line quality is insufficient and fall forward
to a faster speed when line quality is sufficient (%E2).
%E0
Disable line quality monitor and auto-retrain.
%E1
Enable line quality monitor and auto-retrain.
%E2
Enable line quality monitor and fallback/fall forward.
Command:
%L
Line Signal Level
Values:
None
Default:
None
Description:
%L
Returns a value that indicates the received signal level in dBm.
The value returned is a direct indication (DAA-dependent) of
the receive level at the MDP, not at the telephone line connector.
Examples: 009 = -9 dBm, 043 = -43 dBm, and so on.
Command:
%Q
Line Signal Quality
Values:
None
Default:
None
Description:
%Q
Reports line signal quality (DAA-dependent) as a three-digit
number. Returns the higher order byte of the EQM value.
Based on the EQM value, retrain or fallback/fall forward may
be initiated if enabled by %E1 or %E2.
Command:
%U
PCM Code Selection
Values:
n = 0 or 1
Default:
0
Description:
Specifies the PCM code type for 56K modulation. Note, how-
ever, that the modem automatically selects the code type if the
server sends the proper ID.
%U0 Selects µ-Law coding—used in North America and Japan.
%U1 Selects A-Law coding—used outside North America and Japan.
Note:
See also the +MS= command.