|  | 5.5 | ISDN Configuration Tasks
| 5.5.2 | Write the IOS commands to configure ISDN BRI
To configure BRI and enter interface configuration mode, use the interface bri command in global configuration mode. The full syntax of the command is: interface bri number The number argument describes the port, connector, or interface card number. The numbers are assigned at the factory at the time of installation or when added to a system, and can be displayed by using the show interfaces command. The example output shown in the figure configures BRI 0 to call and receive calls from two sites, uses PPP encapsulation on outgoing calls, and uses CHAP authentication on incoming calls.