Datasheet

Functions INSYS Modem 336/56k 4.1 (UL)
5.3.1 V42 Error correction
AT\N<n>
The V.42 error correction includes the protocols LAPM (Link
Access Procedure for Modem) and MNP 4. LAPM is the pre-
ferred error correction.
MNP 4 is supported for compatibility reasons with other MNP
modems. Both methods determine frames to transfer net
data and use CRC (Cyclic Redundancy Check) check sums for
error tests.
In V.42, the possibility exists to have the modem identify if
the partner is a V.42 modem, a MNP modem, or a modem
without error correction. The modem can then autonomously
adjust to the partner.
5.3.2 MNP 2/3/4 error correction
AT\N<n>
AT\A0
AT\A1
AT\A2
AT\A3
The MNP error correction can either be set automatically or
activated via AT commands.
The maximum block size can be set to either
64 byte
128 byte
192 byte
and 256 byte.
5.4 Data Compression
AT%Cn
The modem will identify the type of data compression used
by the other modem, or it is fixed on a certain type or no data
compression.
Data compression is only available for error corrected connec-
tions.
To be able to use data compression, both sides (sender and
recipient) must be able to recognize the same data compres-
sion mode.
24 July 06