Definition of CLLI Code

Common Language Location Identification (CLLI) Codes are eight or eleven character alphanumeric descriptors used to identify telecommunications switches, interconnections, and other network elements and their locations.

The first four characters of a CLLI code identify the city where the equipment is located, the 5th and 6th characters the state, and the 7th and 8th identify the location within that city. Together the first eight characters uniquely identify a Central Office. The last three digits, if present, uniquely identify a piece of equipment at that Central Office.

Example: NYCQNYNWDS0 is a CLLI code for a major NY Central Office.

CLLI is a registered trademark of Telcordia Technologies, Inc.

See also NPA-NXX codes.

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