ISDN Call Identification Display provides a transparent name and number display for all display-equipped telephones within an ISDN network. The feature is transparent in that the same information can be provided at all ISDN facilities. Telephones using this feature should be digital telephones with a 40-character alphanumeric display. The Merlin hybrid sets with 32-character displays (7315H and 7317H) also support this feature.

ISDN Call Identification Display is provided in addition to the normal Telephone Display and Attendant Display features when the network supports end-to-end ISDN connectivity. When both ISDN and DCS display information are received, either the DCS or ISDN call identification information can be displayed. If only ISDN display information is received, information displays in ISDN format.

The display fields that may be used for ISDN are Name, Number, Miscellaneous Call Identification, and Reason for Call Redirection. The display information varies, depending on the type of call, how the call is handled (for example, whether it is redirected or not), and the information is available on the call.