Disabling V.34 Connections; Configuring Isdn; Enabling X.75; Frame Size - 3Com 3C421600A Management Manual

152 C 10: A
HAPTER DVANCED
Disabling V.34
Connections

Configuring ISDN

Enabling X.75

Frame Size

Window Size

Selecting Frame and
Window Size
M C
ODEM ONFIGURATION WITH
The RAS 1500 allows the selective disabling of V.34 connections
depending on whether or not they are made with an x2 capable modem
(Table 42).
Table 42 Disabling V.34 Connections
Action
Allow V.34 and x2 connections
Allow V.34 and x2 connections only with x2
modems
Allow V.34 connections to all modems
Disable V.34 and x2 connections to all
modems
Disable V.34 connections to non-x2 modems,
but allow V.34 connections to x2 modems
Disable V.34 connections to x2 modems
Disable V.34 connections, but allow x2
connections to all modems
S-Register S76, bit 3 can be set only via AT commands at this time.
The RAS 1500 supports X.75 frame and window size configuration.
To enable X.75, set S68=0.
Frame size is the number of data bytes sent in an X.75 frame.
Window size is the number of frames sent before an acknowledge (ACK)
is received.
Window size is an important consideration in the performance of the
system. The larger the window, the more frames that can be transferred
without an acknowledgment. However, the more frames that are
transferred without an acknowledgment, the more the receiver is
required to allocate additional buffer space to handle the incoming
transmissions.
Use the following AT commands to select frame and window size:
CLI/AT
COMMANDS
Command
ATS54.7 = 0
ATS56.6 = 0 (for x2 modems
only)ATS56.7 = 1ATS27.2 =
1ATS13.5 = 1
ATS56.6 = 0ATS76.3 = 0
ATS54.7 = 1
ATS56.6 = 1ATS76.3 = 0
ATS56.6 = 0ATS76.3 = 1
ATS56.6 = 1ATS76.3 = 1