Westermo IDW-90 AT - Manual (Page 13)

13 6620-3200
!%E – 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.
AT!%E0 Disable line quality monitor and auto-retrain.
AT!%E1 Enable line quality monitor and auto-retrain.
AT!%E2 Enable line quality monitor and fallback/fall forward. (default)
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 modulation speeds. The modem will keep falling
back within the current modulation if necessary until the speed reaches 2 400 bit/s (V.34)
or 4 800 bit/s (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.
!+ES – Error Control
This command specifies the initial requested mode of operation when the modem is
operating as the originator, optionally specifies the acceptable fallback mode of operation
when the modem is operating as the originator, and optionally specifies the acceptable
fallback mode of operation when the modem is operating as the answerer. It accepts
three numeric sub parameters:
AT!+ES=[<orig_rqst>[,<orig_fbk>[,<ans_fbk>]]]
<orig_rqst> Decimal number which specifies the initial requested mode of opera-
tion when the modem is operating as the originator. The options are:
0 Not supported.
1 Initiate call with Normal Mode
(also referred to as Buffered Mode) only.
2 Initiate V.42 without Detection Phase. If V.8 is in use, disable V.42
Detection Phase.
3 Initiate V.42 with Detection Phase. (default)
4 Initiate MNP.
6 Not supported.
7 Initiate Frame Tunnelling Mode when connection is complete, and
Data Mode is entered.