Black Box 32144 Manual page 142

MODEM 32144
OFF. Error correction will be
disabled.
MANDATORY. Error correction
will be activated. If the modem
cannot establish a connection
using the type of error correction
selected via the V.42 Selection
option, it will hang up.
TIGHT FIT = AUTO. The modem
will fall back to buffer or non-buffer
mode if conditions do not allow it
to establish a connection using the
type of error correction selected via
the V42 SELECTION screen.
MNP Class (Limit)
Hayes, V.25bis, Dumb, Leased Line
modes (except V.33)
This option is effective only when
MNP error correction is active. It
limits MNP operation to the
selected MNP class or lower.
(MNP classes 1-5 are available.)
In general, the higher MNP classes
provide greater throughput. Class
5, the default, can provide as much
as 2-to-1 data compression over the
transmission link.
50
V.42 Selection Options
The following two options are
available through the V.42
SELECTION screen:
Protocol
Hayes, V.25 bis, Dumb, Leased
line modes (except V.33)
LAPM/MNP. The modem will
attempt to establish a connection
using the V.42 link access protocol
for modems (LAPM). This is the
primary error correction protocol
under the CCITT V.42 standard.
If such a connection cannot be
established (because the other
modem does not support LAPM or
is not configured for LAPM), the
modem attempts to establish a
connection using MNP class 5
as the fallback (alternate) error-
correction protocol.
NOTE
When operating in LAPM
mode, the modem uses V.42
error correction unless V.42
bis is enabled via the V.42
bis option. (V.42 and V.42bis
error correction both use
LAPM.)
LAPM ONLY. The modem will
only attempt to establish an LAPM
connection (will use only V.42 or
V.42 bis error correction).
MNP ONLY. The modem will
only attempt to establish an MNP
connection.