Nortel Networks NN46110-602 manual Appendix B Using serial PPP

168 Appendix B Using serial PPP

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.

3Select 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)

4Enter 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.

5Click Reset to reset the port to the selected baud rate and apply any other modem changes.

NN46110-602