Data Compression Commands; Ds - Data Compression; Dr - Data Compression Reporting - Conexant H08-15355F Reference Manual

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.
<compr_neg> Specifies whether or not the modem should continue to operate if the desired result is not obtained.
<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
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 (see Section 3.5 and Table 3-14).
S95 bit 5 is reset to 0 for +DR=0 and is set to a 1 for +DR=1. The more recent setting of +DR or S95 bit 5, and the W
command setting, determines the actual data compression result code reporting (see S95 Parameter and W Command).
Syntax
+DR=[<value>]
Defined Values
<value> decimal number corresponding to the selected option:
Reporting Current or Selected Values
Command: +DR?
Response: +DR: <current value>
Example: +DR: 1
1118
Command Reference Manual
0 Negotiated; no compression (V.42bis P0=0).
3 both directions, accept any direction (V.42bis P0=11). (Default.)
0 Do not disconnect if V.42bis is not negotiated by the remote modem as specified in
<direction>.
for the defaults and 2048 entry max dictionary.
0 Data compression reporting disabled (no +DR result code transmitted).
1 Data compression reporting enabled (+DR result code transmitted). (Default.)
For the default setting.
Conexant
3-31