Black Box 32144 Manual page 57

- V42, V.42 error correction
(LAPM) is active.
- V42 bis, V.42 bis error correction
(LAPM with data compression)
is active.
- MNP 01 – MNP 05, MNP error
correction is active.
- BUFFER, Buffer mode is active.
- OFFLINE, Modem is off-line.
• RATE. This screen shows the
data rate of the DTE.
7.7 Rate Change Screen
If V.32bis mode and the Rate
Renegotiation Procedure (RRP)
option are both enabled, the
modem will automatically adjust
during data transmission to a
higher or lower data rate,
depending on the receive signal
quality. For diagnostic purposes,
the RATE screen (accessed from
screen 3 of the MAIN MENU) may
be used to manually initiate speed
renegotiation from the front panel,
as explained below.
The RATE screen is displayed
only if V.32 bis mode is enabled
(via Summary Setup, V.32 Mode
option).
CHAPTER 7: Diagnostics
If you select DOWN from the
RATE screen, the modem will fall
back to the next lower speed. If you
select UP, the modem will fall
forward to the next higher speed—
if the signal quality is good enough.
The range within which the
modem can fall forward or fall
back is limited by the minimum
and maximum rates set via the
Speed Limit option. After you
select UP or DOWN, the LCD will
automatically switch to the EIA
status screen so you can see the
result of the rate change request
(i.e., the current data rate, which is
displayed in the lower left corner of
the EIA status screen). However, if
the local modem has reached the
minimum or maximum speed, it
will not switch to the EIA status
screen.
NOTE
A request to increase the
data rate may result in no
change in the data rate if the
signal quality is poor.
If you manually initiate speed
renegotiation with RRP enabled,
the modem will automatically
renegotiate the speed (again) after
receiving good signal quality for
4 seconds. If the originate modem
attempts to negotiate a rate that
is lower than the minimum rate
setting of the answer modem, the
answer modem will disconnect
(GSTN cleardown).
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