INSYS Modem 336 LL 2D/4D 5.x Originate / Answer, Manual

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INSYS Modem 336 LL 2D/4D 5.x Originate / Answer Functions
12.6 Error correction
The INSYS Modem 336 LL 2D/4D 5.x Originate / Answer masters the V.42 error correction
protocol including the Microcom Networking Protocol Levels 2/3/4 (MNP2, MNP3, MNP4)
and the data throughput optimization MNP10. The V.42 error correction includes the
protocols LAPM (Link Access Procedure for Modem) and MNP4. LAPM is the preferred er-
ror correction. MNP 4 is supported to maintain the compatibility with other MNP mo-
dems. Both methods determine frames to transfer net data and use CRC (Cyclic Redun-
dancy 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 cor-
rection. The modem can then autonomously adjust to the partner.
As default, the automatic selection of V.42LAPM or MNP4 or no correction is set.
Configuration with AT commands
To define the type of error correction, use the
command:
AT\N<n>
To set V.42LAP-M or MNP4 error correction
exclusively, use:
AT\N2
Use the following command for the INSYS
Modem 336 LL 2D/4D 5.x Originate / Answer
to automatically select V.42LAP-M, MNP4, or
an error-corrected connection:
AT\N3
To set V.42LAP-M error correction exclusively,
use:
AT\N4
For the buffered mode without error correc-
tion, use:
AT\N0
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