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An explanantion of telecommunications industry CLLI “Silly” Codes April 20, 2009

Posted by HubTechInsider in Definitions, Fiber Optics, Telecommunications, Uncategorized, Wireless Applications.
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What the heck is a “Silly” Code? Allow me to explain…

A CLLI, (pronounced “Silly”) code is a telecommunications industry-standard and is an alphanumeric code of 11 characters, CLLI was developed by Bellcore (now telecordia Technologies) as a method of identifying physical locations and equipment such as buildings, central offices, poles, and antennas. Each CLLI code conforms to one of three basic formats (Network Entity, Network Support Site and Customer Site). Each format, in turn, determines how these six coding elements are used:

Geographical Codes (Example: DNVR = Denver) Typically assigned to cities, towns, suburbs, villages, hamlets, military installations and international airports, geographical codes can also be mapped to mountains, bodies of water and satellities in fixed-earth orbit.

Geopolitical Codes (Example: CO = Colorado) Typically assigned to countries, states and provinces, geopolitical and geographical codes can be combined to form a location identifyer that is unique worldwide.

Network Site Codes (Example: 56 = A Central Office on Main Street) This element is used with geographical and geopolitcal codes to represent buildings, structures, enclosures or other locations at which there is a need to identify and describe one or more functional entities. This category includes central office buildings, business and commercial offices, certain microwave-radio relay buildings and earth stations, universities, hospitals, military bases and other government complexes, garages, sheds and small buildings, phone centers and controlled environmental vaults.

Network Entity Codes (Example: DS0 = A digital switch) This element can be used with geographical, geopolitical and network-site codes to identify and describe functional categories of equipment, administrative groups or maintenance centers involved in the operations taking place at a given location.

Network Support Site Codes (Example: P1234 = A telephone pole) This element can be used with geographical and geopolitical codes to identify and describe the location of international boundaries or crossing points, end points, fiber nodes, cable and facility junctions, manholes, poles, radio-equipment sites, repeaters and tall stations.

Customer Site Codes (Example: 1A101 = A Customer) This element can be used with geographical and geopolitical codes to identify and describe customer locations associated with switched-service networks, centrex installations; Trunk forecasting, cable, carrier or fiber terminations, NCTE, CPE and PBX equipment, military installations, shopping malls, universities and hospitals.

Consider the real-life example of NYCMNY18DS0. The first four characters identify the place name (NYCM is New York City Manhattan). The following two characters identify the state, region, or territory (NY is New York). The remaining five chracters identify the specific item at that place (18DS0 is the AT&T 5E Digital Serving Office on West 18th Street, between Seventh and Eighth Avenues). Phone companies use CLLI Codes for a variety of purposes, including identifying and ordering private lines and trapping and tracing of annoying or threatening calls.

CLLI Code – Facility Identification codes provide unique identification of facilities (cable and carrier systems) between any two interconnected CLLI coded locations. The CLFI code is a variable length, mnemonic code with a maximum of 38 characters. Example: 101T1LSANCA03NWRKNJAA. This example says that there is a T-1 carrier connected between the Los Angeles, California Central Office to the Newark, New Jersey Central Office.

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1. Richard Horn - August 4, 2010

I am looking for more detailed information on CLLI codes, specifically positions 9 – 11, Network Entity Code. When looking at a circuit I would like to know if it connects to a Tadem (Tnn or nnT), Wireless Switch (CMn or nCM), or DACS/DCS (Knn or nnK) for instance. Is there any place available for Network Entity codes?


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