3Com REMOTE ACCESS SYSTEM 1500, Management Manual

Page: 155 / 300

Configuring ISDN
153
Table 43 AT Commands
Relationships
Between Frames and
Windows
Although you can set the frame size on the RAS 1500 up to 2048, use
Table 44 to determine the actual values allowed by the RAS 1500.
Table 44 Frame and Windows Sizes
Viewing Current
Frame and Window
Size Settings
Use the following command to view current frame (*X0) and window
(*X1) size settings:
ATI4
Best Possible
Connection
Every time a call comes in the RAS 1500 goes through a link negotiation
process (called “handshaking”) with the remote device.
The way the RAS 1500 handles outgoing and incoming calls depends on
the call type setting you chose. You can set the RAS 1500 to handle
incoming calls seven different ways:
■
Best possible connection (Universal Connect)
■
Clear channel synchronous
■
V.120 only
■
V.110 only
■
X.75 only
■
Analog modem emulation
■
Synchronous PPP
Setting Command n Value Default size
Frame size AT*X0=n Between 1 and 2048 2048 bytes
Window size AT*X1=n Between 2 and 7 7
Setting Modem Window Size
2048 2
1024 4
512 7