Caller ID

From CDGWiki

Caller ID

a.k.a. Caller Display, Caller Number Display (CND), Calling Line Identification (CLI), Calling Line Identification Presentation (CLIP), Calling Number Identification (CNID)

A supplementary service that allows a caller’s phone number to be displayed when an incoming call is received so that the recipient can see who is calling before deciding whether to answer the call. In a roaming scenario, this number may be delivered to the visited network in two ways:

• Via ISUP – The caller’s phone number is included in the Calling Party Number parameter of the Initial Address Message (IAM). When ISUP call signaling traverses international gateways, this parameter may be modified or dropped.
• Via TIA-41 – The caller’s phone number is included in the CallingPartyNumberString1 parameter of the RouteRequest (ROUTREQ). This parameter is not typically modified or dropped between the home and visited network.

The visited MSC may receive the caller’s phone number via both ISUP and TIA-41 mechanisms. Whether the ISUP Calling Party Number or TIA-41 CallingPartyNumberString1 is used to provide Caller ID is determined by the visited MSC.

For information on international roaming Caller ID, see CDG Reference Document #139.