Information Technology Reference
In-Depth Information
Table17-1
Modem Cannot Send or Receive Data (continued)
Possible Causes
Suggested Actions
Modem speed
setting is not
locked
(continued)
To set the terminal baud rate, use the
speed
line configuration
command. This command sets both the transmit (to terminal)
and receive (from terminal) speeds.
Syntax:
speed
bps
Syntax Description:
•
bps
—Baud rate in bits per second (bps). The default is 9600
bps.
Example:
The following example sets lines 1 and 2 on a Cisco 2509 access
server to 115200 bps:
line 1 2
speed 115200
Note:
If you cannot use flow control for some reason, limit the
line speed to 9600 bps. Faster speeds likely will result in lost
data.
3.
Use the
show line
exec command again, and confirm that
the line speed is set to the desired value.
4.
When you are certain that the access server or router line is
configured for the desired speed, initiate a reverse Telnet
session to the modem via that line. For more information,
see the section “Establishing a Reverse Telnet Session to a
Modem,” in Chapter 16.
5.
Use a modem command string that includes the lock DTE
speed command for your modem. See your modem
documentation for exact configuration command syntax.
Note:
The modem AT command to lock DTE speed, which
might also be referred to as
port rate adjust
or
buffered mode
,is
often related to the way in which the modem handles error
correction. This command varies widely from one modem to
another.
Locking the modem speed ensures that the modem always
communicates with the Cisco access server or router at the speed
configured on the Cisco auxiliary port. If this command is not
used, the modem reverts to the speed of the data link (the
telephone line) instead of communicating at the speed
configured on the access server.
