60
CSU/DSU MS DBU
9.3.3 DBU O
PTIONS FOR
V.34 C
ARD
Table 9-3 shows the equivalent AT commands for setting Error Control,
Flow Control, and Compression options.
Error Control
This option determines the type of error control to be negotiated at the start
of a V.34 modem connection. The factory-default setting is AUTO V.42/MNP.
Flow Control
This option is used to select the type of flow control used by the V.34 modem.
The factory-default setting is CTS Only.
Compression
This option is used to select V.42 bis data compression for V.32 bis or V.34
operation when running asynchronously. When compression is enabled,
data-throughput speeds as high as 57.6 kbps may be achieved. For synchronous
applications, the speed is limited to a maximum of 33.6 kbps for the V.34 Card.
The factory-default setting is Enabled.
Table 9-3. DBU Options AT Commands for V.34 Card
DBU Options
CMD AT
Description
Error Control
1=BUFFERED
\N0
Normal operation. No error control. Allows
speed matching, buffering, and flow control.
2=DIRECT
\N1
Direct operation. No error control, no buffer,
and no flow control.
3=RELIABLE MNP
\N2
Reliable MNP operation. Uses MNP
®
error
control.
4=AUTO MNP
\N3
Auto-Reliable MNP operation. Tries MNP
error control first; uses normal operation if
necessary.
5=RELIABLE V.42
\N4
Reliable V.42 (LAPM) operation. Uses V.42
(LAPM) error control. If V.42 (LAPM) error
control cannot be used, the call is
disconnected.
6=REL. V.42/MNP
\N5
Reliable V.42 (LAPM) or MNP operation.
Uses either V.42 (LAPM) or MNP error
control. If neither can be used, the call is
disconnected.