CISCO IOS in a Nutshell

Name

isdn answer1, isdn answer2 — interface

Synopsis

isdn answer1 [called-party-number][:sub-address]
no isdn answer1 [called-party-number][:sub-address]

isdn answer2 [called-party-number][:sub-address]
no isdn answer2 [called-party-number][:sub-address]

Configures

Verification of the called party

Default

None

Description

This command configures the interface to verify that the telephone number being called (which is reported by the ISDN switch as part of call setup) matches the telephone number of the router. By default, calls are processed without verification. If this command is configured, the router verifies the incoming called-party-number before allowing the connection. Using this command can reduce the potential for confusion when several ISDN devices share the same ISDN local loop. Use isdn answer2 to verify a second called-party number.

To list a called-party-number or a sub-address, use any number of digits up to 50; an x specifies a wildcard. You must specify either the called-party-number or the sub-address, but you are not required to specify both. If you specify only one, the other is taken as a wildcard.