Error Correction - insys icom 336 LL Manual

INSYS 19" 336 LL
11.6

Error correction

The INSYS 19" 336 LL Modem masters the V.42 error correction protocol including the
Microcom Networking Protocol Levels 2/3/4 (MNP-2, MNP-3, MNP-4) and the data
throughput optimization MNP-10. The V.42 error correction includes the protocols LAPM
(Link Access Procedure for Modem) and MNP-4. LAPM is the preferred error correction.
MNP-4 is supported to maintain the compatibility with other MNP modems. Both meth-
ods determine frames to transfer net data and use CRC (Cyclic Redundancy Check) check
sums for error tests. In V.42, there is the option 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.
As default, the automatic selection of V.42 LAPM or MNP-4 or no correction is set.
Configuration with AT commands
To define the type of error correction, use the
command
To set V.42 LAPM or MNP-4 error correction
exclusively, use the command
Use the following command for the INSYS 19"
336 LL Modem to automatically select V.42
LAPM, MNP-4, or an error-corrected connec-
tion:
To set V.42 LAPM error correction exclusively,
use the command
For the buffered mode without error correc-
tion, use the command
AT\N<n>
AT\N2
AT\N3
AT\N4
AT\N0
Functions
37