Synxcom SM9234D, User Manual

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AT Commands
Page 98
3.2.6 Data Compression Commands
This section contains parameters to condition modem use of standard ITU-T
V.42bis Data Compression Procedures.
+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 Value
<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 the desired direction(s) of operation of the data
compression function; from the DTE point of view.
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)
+DS44 - V.44 Compression Select
This extended-format compound parameter controls the V.44 data compression
function.
Syntax +DS44=[<direction>[,< compress_negotiation
>[,<capability>[,<max_codewords_tx>
[,<max_codewords_rx>[,<max_string_tx>[,<max_string_rx>[,
<max_history_tx>
[,<max_history_rx>]]]]]]]]]
Defined Value
<direction> Decimal number that specifies the desired direction(s) of