Toshiba V.92 - Manual (Page 96)

96 MNP and V.42
Operation modes
5.375 x 8.375 ver 2.4.0
The protocol of both modems must be the same. Therefore, if
the remote modem supports only class 3 or below, the
protocol for the remote modem will be used. If the remote
modem does not use MNP, the communication will be made
at the speed of the remote modem.
V.42 error correction
The V.42 (ITU-T-Rec V.42) protocol is recommended by the
ITU (International Telecommunications Union). V.42
specifies two kinds of protocols, LAP-M (Link Access
Procedure for Modem) and MNP classes 2, 3, and 4. This
protocol first tries to establish a link to the remote modem
with LAP-M. If it is unsuccessful, it tries to connect with
MNP. Although this modem uses class 4 correction, it can
connect in class 5 to remote modems that support class 5.
Operation modes
The operation mode depends on whether an error-correction
protocol is being used.
Normal mode
Errors are not corrected, even if communication speed is
different between a personal computer and modem, or
between modems, the buffers in the modem and the flow
control function permit communication without changing
communication speed.
Reliable mode
This mode is used with MNP or V.42 protocols to ensure
error-free communication.