CISCO IOS in a Nutshell

Name

isdn caller — interface

Synopsis

isdn caller phone-number [callback]
no isdn caller phone-number [callback]

Configures

ISDN caller ID screening

Default

Disabled

Description

If your ISDN switch supports caller ID, this command lets you specify a phone-number from which incoming connections are allowed. If the inbound call does not originate from this number, it will be rejected. You may use the letter x in the phone number as a wildcard character; for example, 458-xxxx means “any number in the 458 exchange.” The callback keyword causes the router to reject the call and initiate a callback to the caller’s number; this feature may help you manage phone costs.