Hardware manual

5901 High Speed Dialup Modem Hardware Manual
October 19, 2007
67
0 Disables data compression. Resets S46 bit 1.
1 Enables MNP 5 data compression negotiation. Resets S46 bit 1.
2 Enables V.42 bis data compression. Sets S46 bit 1.
3 Enables both V.42 bis and MNP 5 data compression. Sets S46 bit 1. (Default.)
Result Codes:
OK n = 0, 1, 2, or 3.
ERROR Otherwise.
10.7.4 %En- Enable/Disable Line Quality Monitor and Auto-Retrain or
Fallback/Fall Forward
Controls whether or not the modem will automatically monitor the line quality and request a retrain
(%E1) or fall back when line quality is insufficient or fall forward when line quality is sufficient
(%E2). The parameter value, if valid, is written to S41 bits 2 and 6.
If enabled, the modem attempts to retrain for a maximum of 30 seconds.
Command: %En
n Decimal number corresponding to the selected option.
0 Disable line quality monitor and auto-retrain.
1 Enable line quality monitor and auto-retrain.
2 Enable line quality monitor and fallback/fall forward. (Default.)
Result Codes:
OK n = 0, 1, or 2.
ERROR Otherwise.
Fallback/Fall Forward
When %E2 is active, the modem monitors the line quality (EQM). When line quality is insufficient,
the modem will initiate a rate renegotiation to a lower speed within the V.34/V.32 bis/V.32 (RC336)
modulation speeds. The modem will keep falling back within the current modulation if necessary
until the speed reaches 2400 bps (V.34) or 4800 bps (V.32). Below this rate, the modem will only do
retrains if EQM thresholds are exceeded. If the EQM is sufficient for at least one minute, the modem
will initiate a rate renegotiation to a higher speed within the current modulation speeds. The rate
renegotiations will be done without a retrain if a V.32 bis connection is established.
Speeds attempted during fallback/fall forward are those shown to be available in the rate sequences
exchanged during the initial connection. Fallback/fall forward is available in error correction and
normal modes, but not in direct mode or synchronous mode with external clocks.
10.7.5 %L - Report Line Signal Level
Returns a value, which indicates the received signal, level. The value returned is a direct indication
(DAA dependent) of the receive level at the MDP, not at the telephone line connector. For example,
009 = -9 dBm, 043 = -43 dBm, and so on.
Result Codes:
OK