Nortel Networks NN46110-602 - Manual (Page 168)

168 Appendix B Using serial PPP
NN46110-602
to access all management services (HTTP, Telnet, FTP, SNMP) through
the Web interface. Once you establish a session through PPP, the serial
interface acts as a private WAN interface with an internal IP address
(0.0.1.35).
• Auto detect—automatically detects whether the connected device is using
PPP or serial menu mode at startup. The VPN Router cannot determine
the device’s baud rate, nor can it determine a change from PPP to serial
menu mode, except upon startup. Auto Detect checks the mode each time
the VPN Router is restarted. When performing its Auto Detect check, the
VPN Router sends out AT command set characters to configure a modem
if one is attached.
When the VPN Router is in Auto Detect mode, and if a terminal session
is connected and the terminal baud rate is the same as the VPN Router’s,
the terminal displays the AT command sets on the window. Simply press
Enter several times until a serial menu session starts. It is better to use
Auto Detect Mode than PPP Mode. If you use PPP mode, it can leave the
VPN Router in a state that you can never manage it from the serial
interface menu directly. If this happens, you can still manage the VPN
Router through a PPP application (such as Dial-Up Networking). Directly
connecting a serial cable and running Hyper Terminal does not work
because the interface only recognizes PPP.
3 Select one of the following Baud Rates to match the baud rate of your
terminal. After you select the baud rate, you must click Reset to change the
port to the selected baud rate. This option is necessary for PPP if a modem
initialization string specifies a fixed baud rate.
• 57600
• 38400
• 19200
• 9600 (default)
4 Enter the modem initialization string. See the manufacturer’s documentation
to learn the vendor-specific character initialization string. Preconfiguring the
modem and using the VPN Router’s default initialization string (ATZ)
provides the best results.
A sample 3Com/US Robotics 56K modem initialization string that instructs
the external modem to connect at 19,200 Kb/s is ATZAT&B1AT&N10.
5 Click Reset to reset the port to the selected baud rate and apply any other
modem changes.