Insys Modem 56k 4.1 11-02-01-01-40.028 Manuale Utente

Functions 

INSYS Modem 336/56k 4.1 (UL) 

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. 

 

AT\N<n> 

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.  

 

 

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. 

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July 06