The EAI/TIA 568 standard for premises cabling is used by most manufacturers and users of premises cabling systems in the US. Internationally, IEC/ISO 11801 is very similar for fiber optics, although there are differences in various countries. TIA-568 has been under continual revision since its inception. The current version is "568 B.3" covering fiber optics. It includes some major changes from earlier versions for fiber optics. TIA 568 "C" is expected to be published sometime in 2008, but fiber optic cabling changes are not substantial. These include:
1. Adds 50/125 micron fiber (OM2 or OM3) as an alternative fiber type and specifies performance.
2. Allows alternate connectors to the SC, esp. small form factor connectors.
3. Adds performance standards for all connectors.
4. Includes bend radius specifications for cables.
5. Specifies requirements for connecting hardware.
Fiber Optic Cable Performance Standards
568 B3 adds 50/125 fiber as an acceptable type and specifies the performance of cabled fiber as follows:
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Note that these specs are quite conservative, compared to what is routinely available in the marketplace, especially now that more fiber manufacturers are offering high bandwidth 62.5/125 fiber and 50/125 fiber with even higher bandwidth than OM3 (currently being called OM3+ by most manufacturers, but an OM4 spec with 850 nm BW of approximately 3500 MHz-km.) The spec notes also that the cable manufacturer can use the fiber manufacturer's data on bandwidth, so they do not have to test it.
Hybrid Cables
The standard notes that hybrid cables are permitted, with markings per ANSI/EIA/TIA-598-A. ( Hybrid cables contain both multimode and singlemode fibers.)
Premises Cables
Horizontal cables with 2-4 fibers require a 25 mm bend radius after installation or 50 mm while being pulled with a tension of 50 pounds (222 N).
Other premises cables require a bend radius of 10 times the cable outside diameter unloaded and 15 times the OD when under the maximum rated pulling tension for that cable.
Outside Plant Cables
The standard calls for water-blocked cables with a minimum pulling tension of 600 pounds (2670 N).
Minimum bend radius is 20 times the cable diameter under max rated pulling tension and 10 times unloaded.
Drop Cables
The standard adds a definition for "drop cables," low fiber count cables used to connect high fiber count cables to smaller fiber count cables or patchcords in a single location. These cables must withstand 300 pounds pulling tension (1335 N).
Connectors and Connecting Hardware
Any connector design is permitted as long as it has a FOCIS document (Fiber Optic Connector Intermateability Standard). All with FOCIS documents are acceptable.
Color Codes: Multimode connectors are beige for 62.5/125 fiber, black for 50/125 fiber, singlemode are blue, angle-polished singlemode are green, and outlets are also color coded accordingly. Cable color codes are the same as TIA-598.
Duplex connectors are keyed and are always crossover - that is Position A of one connector connects to Position B on the other end! Patchcords have this feature too, to permit correct connection of transmitters and receivers!
Outlet boxes must have provision for termination of at least 2 fibers.
Patch panels and outlets must provide unique identification for the connecting cabling.
Connector Mating Loss:
Remember these connector losses are maximum values. The loss is high to allow prepolished/splice connectors which have higher loss than adhesive/polish connectors. Users may specify lower loss for installations if agreed upon by all parties involved.
Notes:
Loss is tested per FOTP-171, single cable reference.
Maximum loss spec holds over temperature (0-60C), humidity (95% @ 40C), impact, pull strength of coupling (7.4 lb./33N), durability (500 matings), cable retention (11 lbs./50 N straight, 4 lbs./19N at 90)flex and twist.
Splices
Fusion or mechanical splices shall not have a loss of more than 0.3 dB. Multimode splices must have a return loss of better than 20 dB. Singlemode splices must be better than 26 dB ORL for general applications, 55 dB ORL for CATV broadband analog video.
Related Fiber Optic Components Links
•Types of Fiber Optic Cables
•Fiber Optic Cable Plant Link Loss Budget Analysis
• Fiber Optic Connector Types
•Troubleshooting Fiber Optic Transmitters & Receivers
•Fiber Optic Couplers & Splitters
•Fiber Optical Amplifiers