i-modul Modem 144/56k
Functions
6.6
Data Compression
The i-modul Modem 144/56k 3.0 basic supports various data compression types.
During the connection setup, it will automatically detect the type of data
compression used by the remote terminal, or it is set to a certain type of data
compression. Data compression is only available for error corrected connections.
To be able to use data compression, both sides (sender and recipient) must be able
to at least recognize and support the same data compression mode.
The default setting is the automatic selection of MNP5 and V42.bis and V.44 data
compression (
AT%C3
).
Configuration with AT commands
To select the compression type, use:
AT%C<n>
To completely switch off the compression,
use the following commands:
AT%C0
AT+DS44=0
To select the MNP4 compression:
AT%C1
To select the V42bis and V.44 data
compression if they are switched on (see
below):
AT%C2
To select the V42bis and MNP5 data
compression if V42.bis compression is
switched on (see below):
AT%C3
To switch on V.42bis compression:
AT%C2
To switch on V.44 compression:
AT+DS44=3
To switch off V.42bis compression:
AT%C0
To switch off V.44 compression:
AT+DS44=0
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