ISDN Caller ID Name

No caller ID (CID) names showing up on phones? Run the usual debug isdn q931 and debug isdn q921 to make sure that the CID name is coming from the provider. If it is, add isdn supp-service name calling to the serial port for the ISDN trunk. Then retest.

Source: https://supportforums.cisco.com/docs/DOC-8873

Example:

interface Serial0/3/0:23
 no ip address
 encapsulation hdlc
 isdn switch-type primary-ni
 isdn incoming-voice voice
 isdn map address . plan unknown type unknown
 isdn supp-service name calling
 isdn sending-complete
 isdn outgoing ie redirecting-number
 trunk-group ALL_T1E1
 no cdp enable