AOpen FM56, Manual, Page: 66 / 127

3.2.6 Data Compression Commands
This section contains parameters to condition modem use of standard ITU-T V.42 bis
Data Compression Procedures.
3.2.6.1 +DS - Data Compression
This extended-format compound parameter controls the V.42bis data compression
function if provided in the modem. It accepts four numeric subparameters:
Syntax
+DS=[<direction>[,<compr_neg>[,<max_dict>[,<max_string>]]]]
Defined Values
<direction> Specifies the desired direction(s) of operation of the data compression
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 (2048 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: +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: +DS=?
Response: +DS: (<direction> range),(< compr_neg > range),(<max_dict>
range),(<max_string> range)
Example: +DS: (0,3),(0),(2048),(32)
3.2.6.2 +DR - Data Compression Reporting
This extended-format numeric parameter controls whether or not the extended-format
"+DR: " intermediate result code is transmitted from the modem to the DTE.
Syntax
+DR=[<value>]
Defined Values
<value> decimal number corresponding to the selected option:
0 = Data compression reporting disabled (no +DR result code transmitted).
1 = Data compression reporting enabled (+DR result code transmitted). (Default.)
Reporting Current or Selected Values
Command: +DR?
Response: +DR: <current value>
Example: +DR: 1 For the default setting.
Reporting Supported Range of Parameter Values
Command: +DR=?
Response: +DR: (<value> range)