Basic Configuration Using the Command-Line Interface
Testing Asynchronous Shell Connections
36
Cisco AS5350XM and Cisco AS5400XM Universal Gateways Software Configuration Guide
•
Basic modem links
•
Basic IP functionality to support shell sessions
The Cisco IOS software provides a command-line interface (CLI) called the EXEC that can be accessed
by dialing in with a modem. The EXEC provides access to terminal-shell services (no PPP) to do the
following:
•
Modify configuration files
•
Change passwords
•
Troubleshoot possible problems including modem connections
•
Access other network resources by using Telnet
During this task, some administrators try to make complex services function, such as PPP-based web
browsing. Do not jump ahead. Many other elements still must be configured (for example, PPP and
IPCP). The asynchronous-shell test ensures that the EXEC login prompt can be accessed by a client
modem. Taking a layered approach to building a network isolates problems and saves you time.
To test asynchronous-shell connections, perform the following steps:
Step 1
Locate a client PC, client modem, and analog line. From the client PC, open a terminal emulation
program (such as HyperTerminal, not dial-up networking) and connect to the client modem.
Figure 4
shows the network environment for this test.
Figure 4
Test Environment
Step 2
From a terminal emulation program, test your EIA/TIA-232 connection to the client modem. Enter the
at
command. The modem returns the prompt
OK
.
at
OK
Note
To learn more about the
at
command set, see the various references available online at the
Technical Assistance Center website at
http://www.cisco.com/pcgi-bin/Support/PSP/psp_view.pl?p=Internetworking:ASYNC&s=Impl
ementation_and_Configuration
Step 3
Dial the PRI telephone number assigned to the gateway (in this example, the number is 5554100). After
the modem successfully connects, a connect message appears.
atdt 5554100
CONNECT 33600/REL - LAPM
Client PC
Default
gateway
Client
modem
PSTN
POTS line
PRI lines
56093
V
V
Cisco gateway
with integrated
modems