Fiber Optic Outside and Inside Plant today




The POP at the building on California Ave in SLC has CLLI code (COMMON LANGUAGE Location Identifier Code and pronounced silly) and is an identifier used within the North American telecommunications industry to specify the location and type of a piece of telecommunications equipment. In this case SLKCUTB00 indicates Fiber Optic Facilities that is at 1400 west California Ave in SLC UT. SLKC for SLC UT for Utah and B00 designating 1400 west California Ave.

Originally, the CLLI code was used by Bell Telephone companies, but with deregulation Competitive and Interstate carriers required interconnect with the Incumbent Carriers which were the old Bell companies, as more interconnections were made CLLI code became universal. CLLI codes are now managed and issued by Telcordia, which now holds trademarks on the names “Common Language” COMMON LANGUAGE® and “CLLI” CLLI™ Codes Tec

COMMON LANGUAGE Location Codes (CLLI Codes) are now used worldwide to identify and describe three types of locations:

Network sites: These include The ILEC central office CLEC and IXC network centers or Points of Presence (POP) which can located in business and commercial offices, there own freestanding buildings but can also include microwave radio structures and even Satellite earth stations.
, REGEN and cable facility junctions whether in a walk in shelter or Fiber/C
Network support sites: Are international boundary crossing/meet/end points, fiber optic transport facilities like OPAMP opper Serving Area Interface but also manholes, poles and repeaters.



Customers sites: These include customer locations and associated circuit terminations, facilities or equipment for each specific customer.

Geographical Codes
(Example: SLKC = Salt Lake City)
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: SLKC = Salt Lake City)

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 satellites in fixed-earth orbit.
Geopolitical Codes
(Example: UT = UT)

Typically assigned to countries, states and provinces, geopolitical and geographical codes can be combined to form a location identifier that is unique worldwide.



Network-Site Codes
(Example: MA = The Main central office in the City which in this case is First South and State Street)

This element is used with geographical and geopolitical 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: DS1= 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.
SLKCUTMADS1 which is

State: UT
English Name: SLKC-MAIN
Switch Type: Northern Telecom DMS100 (Digital)
Host CLLI (if remote):
Status: ()
LATA: Utah (660)
Exchanges Served: 37
Street Address: 70 S State St
Salt Lake City, UT 84111-1507

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 toll stations.
Customer Site Codes
(Example: B00 = Our customers Telecom closet) or examples of the DS3 circuit Id’s:
As you can see in the examples the geographical and geopolitical codes to identify the CLEC OX (for XO) T3 indicating a DS3 and then a circuits number like 01.
Customer Site Codes will describe customer locations associated with switched-service networks, cable, carrier or fiber terminations, network carrier terminating equipment (NCTE), Customer Premises Equipment (CPE) and PBX equipment, military installations, shopping malls, universities and hospitals.


Fiber Optics


Not sure where I got this, as a note I did write this section as found it somewhere on the web a few years back:

Optical communication systems date back to the 1790s, to the optical semaphore telegraph invented by French inventor Claude Chappe. In 1880, Alexander Graham Bell patented an optical telephone system, which he called the Photophone. However, his earlier invention, the telephone, was more practical and took tangible shape. The Photophone remained an experimental invention and never materialized. During the 1920s, John Logie Baird in England and Clarence W. Hansell in the United States patented the idea of using arrays of hollow pipes or transparent rods to transmit images for television or facsimile systems.

In 1954, Dutch scientist Abraham Van Heel and British scientist Harold H. Hopkins separately wrote papers on imaging bundles. Hopkins reported on imaging bundles of unclad fibers, whereas Van Heel reported on simple bundles of clad fibers. Van Heel covered a bare fiber with a transparent cladding of a lower refractive index. This protected the fiber reflection surface from outside distortion and greatly reduced interference between fibers.

Abraham Van Heel is also notable for another contribution. Stimulated by a conversation with the American optical physicist Brian O’Brien, Van Heel made the crucial innovation of cladding fiber-optic cables. All earlier fibers developed were bare and lacked any form of cladding, with total internal reflection occurring at a glass-air interface. Abraham Van Heel covered a bare fiber or glass or plastic with a transparent cladding of lower refractive index. This protected the total reflection surface from contamination and greatly reduced cross talk between fibers. By 1960, glass-clad fibers had attenuation of about 1 decibel (dB) per meter, fine for medical imaging, but much too high for communications. In 1961, Elias Snitzer of American Optical published a theoretical description of a fiber with a core so small it could carry light with only one waveguide mode. Snitzer’s proposal was acceptable for a medical instrument looking inside the human, but the fiber had a light loss of 1 dB per meter. Communication devices needed to operate over much longer distances and required a light loss of no more than 10 or 20 dB per kilometer.

By 1964, a critical and theoretical specification was identified by Dr. Charles K. Kao for long-range communication devices, the 10 or 20 dB of light loss per kilometer standard. Dr. Kao also illustrated the need for a purer form of glass to help reduce light loss.

In the summer of 1970, one team of researchers began experimenting with fused silica, a material capable of extreme purity with a high melting point and a low refractive index. Corning Glass researchers Robert Maurer, Donald Keck, and Peter Schultz invented fiber-optic wire or “optical waveguide fibers” (patent no. 3,711,262), which was capable of carrying 65,000 times more information than copper wire, through which information carried by a pattern of light waves could be decoded at a destination even a thousand miles away. The team had solved the decibel-loss problem presented by Dr. Kao. The team had developed an SMF with loss of 17 dB/km at 633 nm by doping titanium into the fiber core. By June of 1972, Robert Maurer, Donald Keck, and Peter Schultz invented multimode germanium-doped fiber with a loss of 4 dB per kilometer and much greater strength than titanium-doped fiber. By 1973, John MacChesney developed a modified chemical vapor-deposition process for fiber manufacture at Bell Labs. This process spearheaded the commercial manufacture of fiber-optic cable.

In April 1977, General Telephone and Electronics tested and deployed the world’s first live telephone traffic through a fiber-optic system running at 6 Mbps, in Long Beach, California. They were soon followed by Bell in May 1977, with an optical telephone communication system installed in the downtown Chicago area, covering a distance of 1.5 miles (2.4 kilometers). Each optical-fiber pair carried the equivalent of 672 voice channels and was equivalent to a DS3 circuit. Today more than 80 percent of the world’s long-distance voice and data
A fiber-optic cable is composed of two concentric layers, called the core and the cladding, as illustrated below





The core and cladding have different refractive indices, with the core having a refractive index of n1, and the cladding having a refractive index of n2. The index of refraction is a way of measuring the speed of light in a material. Light travels fastest in a vacuum. The actual speed of light in a vacuum is 300,000 kilometers per second, or 186,000 miles per second.
The index of refraction (IOR) is a way of measuring the speed of light in a material. Light travels fastest in a vacuum, such as outer space. The actual speed of light in a vacuum is 300,000 kilometers per second, or 186,000 miles per second.

Index of Refraction is calculated by dividing the speed of light in a vacuum by the speed of light in some other medium.
The Index of Refraction of a vacuum by definition has a value of 1.

For the sake of simplicity, typical values are provided here in Figure 5. Notice that the typical value for the cladding of an optical fiber is 1.46. The core value is 1.48. The larger the index of refraction, the more slowly light travels in that medium.
When a light ray traveling in one material hits a different material and reflects back into the original material without any loss of light, total internal reflection occurs.


Since the core and cladding are constructed from different compositions of glass, theoretically, light entering the core is confined to the boundaries of the core because it reflects back whenever it hits the cladding. For total internal reflection to occur, the index of refraction of the core must be higher than that of the cladding.
Single-mode (SM) fiber allows for only one pathway, or mode, of light to travel within the fiber. The core size is typically 8.3 µm. Single-mode fibers are used in applications where low signal loss and high data rates are required, such as on long spans where repeater/amplifier spacing needs to be maximized.

Multimode (MM) fiber allows more than one mode of light. Common MM core sizes are 50 µm and 62.5 µm. Multimode fiber is better suited for shorter distance applications. Where costly electronics are heavily concentrated, the primary cost of the system does not lie with the cable. In such a case, MM fiber is more economical because it can be used with inexpensive connectors and LED transmitters, making the total system cost lower. This makes MM fiber the ideal choice for short distance, lower bandwidth applications.


TIA-598-B Fiber Optic Cable Standard Color Code

1 Blue
7 Red

2 Orange
8 Black

3 Green
9 Yellow

4 Brown
10 Violet

5 Slate
11 Rose

6 White
12 *Aqua

* 13 fibers and higher, the color code is repeated every 12 and the buffered fibers or subcables are striped once for every additional 12 according to the TIA-598-B specifications.




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