Westermo IDW-90 AT User Manual

Page 12

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!+DS – Data Compression
This extended-format compound parameter controls the V.42bis data compression func-
tion if provided in the modem. It accepts four numeric sub parameters:

AT!+DS=[<direction>[,<compr_neg>[,<max_dict>[,<max_string>]]]]

<direction>

 Specifies the desired direction(s) of operation of the data compres-
sion function; from the DTE point of view. 
0  Negotiated; no compression (V.42bis P0=0). 
3  both directions, accept any direction (V.42bis P0=11) (default)

<compr_neg>   Specifies whether or not the modem should continue to operate if 

the desired result is not obtained.

0   Do not disconnect if V.42bis is not negotiated by the remote 

modem as specified in <direction>

<max_dict>

 Specifies the maximum number of dictionary entries (2 048 entries) 
which should be negotiated (may be used by the DTE to limit the 
codeword size transmitted, based on its knowledge of the nature of 
the data to be transmitted).

<max_string>   Specifies the maximum string length (32 bytes) to be negotiated 

(V.42bis P2).

Reporting Current or Selected Values

Command: 

AT!+DS?

Response: 

+DS: <direction>,<compr_neg>,<max_dict>,<max_string>

Example:

+DS: 3,0,2048,32 for the defaults and 2048 entry max dictionary

Reporting Supported Range of Parameter Values

Command: 

AT!+DS=?

Response: 

 +DS: (<direction>range),(<compr_neg>range), (<max_
dict>
range),(<max_string>range)

Example:

+DS: (0,3),(0),(2048),(32)

E – Local echo
Selects the local echo in command mode.

ATE0 

No local echo

ATE1

Local echo on in command phase (default)

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