Connecting Hardware
OSP Twisted-Pair Connecting Hardware
General
The connecting hardware includes terminal blocks that are used for transition from distribution cable to service wire, and cross-connect blocks that are used for cross-connection between feeder and distribution cables.
Environmental Compatibility
Connecting hardware shall:
- function for continuous use within the temperature range of -40°C to 70°C (-40°F to 158°F)
- allow for connecting and removing wires from -18°C to 50°C (0°F to 122°F)
- have terminals that are resistant to corrosion from moisture, atmosphere, UV degradation, insecticides and herbicides.
Materials
Metal components shall:
- be resistant to or protected against general corrosion,stress corrosion cracking and pitting.
- not produce significant galvanic corrosion effects on other metals in
pedestal terminal closures or aerial cable terminals.
Plastic parts shall:
- be resistant to fungi, heat, solvents, and stress cracking agents
- be compatible with metals and other materials used in the manufacture of cable
- non-corrosive to metals
- resist deterioration when exposed to chemical pollutants and UV radiation.
Transmission
The transmission requirements of connecting hardware used in the OSP shall comply with connecting hardware requirements of ANSI/TIA/EIA 568-B.2. It should be noted here that ANSI/TIA/EIA-B generally applies to the intra building components. However, these components are the same ones used to terminate and splice OSP cable. The testing performed on OSP cable is not subject to the same testing for the permanent link or channel tests of the intra building cable, unless the OSP cable is a category rated cable which is part of the loop being tested. An example may be a school having a portable classroom located within the 100 meter channel limitation that uses a category rated OSP cable to go from the main building to the portable.
Terminal Block Requirements
General
Terminal blocks provide a means to connect service wire to distribution cable. Terminals are provided with a means for connecting each terminal pair to the distribution cable, and a means for connecting the service wire to the terminal block. OSP terminal blocks should be the insulation displacement contact (IDC) type, the most common being 110, just like the 110 block found in voice and data communications. Terminal blocks may be stubbed to provide conductors between the terminal block and connection point to the cable. They are typically housed in an enclosure designed to protect the terminal block from moisture and sun exposure. The following requirements apply to connecting hardware used as terminal blocks in OSP.
Wire Compatibility, Pair Identification and Mounting
Terminal blocks shall:
- be compatible with the service wire used for an application.
- have the recommended wire gauges for each block indicated by the manufacturer
- shall meet electrical requirements for the smallest designated gauge conductor after connecting and disconnecting the largest designated gauge conductor
- provide a means for identifying individual terminal pairs
- provide a means for idnetifying the polarity of tip and ring of each pair
- allow for fastening to a wood, steel or plastic backboard
Test Points
Terminal blocks shall
allow access to test points for each pair without disconnecting the service
wire from the terminal or puncturing the wire insulation.
NOTE - High impedance probes are needed to use the test access points for
live
high frequency applications.
Stub cable
The stub cable shall use standard color coding to indicate individual pairs and tip and ring.
Cross-Connect Block Requirements
General
Cross-connect blocks are used in OSP to connect feeder pair to distribution pair. Cross connect blocks may be located in cabinets, on walls or possibly even a rack designed for high density applications. In a cross connect scenario the incoming feeder lines pairs are each terminated on a feeder cross connect block, following the appropriate color codes. The distribution cable for the building is also terminated on a distribution cross connect block following the proper color codes. These two blocks are then connected, pair by pair using cross connect or jumper wire.
cross-connect blocks for OSP cable pairs should be the IDC type, the most common being the 110 style. Cross-connect blocks are typically available in multiples of 10- or 25-pair.
Cross-connect blocks in the outside environment are subject to:
- temperature and humidity extremes
- industrial or coastal atmospheres
- applied chemicals such as insecticides, herbicides, cleaners, and other solvents.
Wire Compatibility,
Identification and Termination
Cross-connect blocks shall:
- be compatible with the feeder cable, distribution cable, and jumper wire used
- have the recommended cable and wire gauges for each block indicated by the manufacturer
- meet electrical requirements for the smallest designated gauge conductor after connecting and disconnecting the largest designated gauge conductor
- locate tip on the left and ring on the right for horizontal spacing, or tip above the ring terminal for vertical spacing
- provide a means for identifying individual terminal pairs either on the block or an adjacent surface
- have removable red markers available for attachment to a pair termination to designate special circuits
- have markers withstand all environmental exposure required for the block without becoming unserviceable
- be designed to eliminate the possibility of electrical shorts between any two terminals during jumper wire placement
Test Points
All terminals shall allow access to test points for each pair without disconnecting the jumper wire from the terminal or puncturing the wire insulation.
Terminal Density
Terminals shall be arranged to allow for a neat and compact installation, and allow for proper jumper terminations.
Wiring Harness
When a wiring harness is used to connect the cross-connect block to the distribution cable, the cable shall use standard color coding to indicate individual pairs and to indicate tip and ring polarity.
Optical Fiber Connectors
Optical fiber connectors shall meet the requirements of ANSI/TIA/EIA-568-B.3. The two most often used connectors are the SC or 568SC duplex, or the ST connector. The SC is recognized for all new installations, and the ST is grandfathered for existing applications. Most fiber optic connectors are located within a building or environmentally controlled structure.
Optical Fiber Patch Cords and Cross-Connect Jumpers
In environmentally conditioned spaces, patch cords and jumpers shall meet the requirements of ANSI/TIA/EIA-568-B.3. Additionally, if the devices are located in an environmentally unconditioned OSP spaces, patch cords and jumpers shall meet environmental test requirements of Bellcore GR-326.
Optical Fiber Cable Installation Requirements
The location and protection
of the optical fiber cable shall comply with ANSI/TIA/EIA-590-A. All metallic
components of the cable, except for metallic transmission media, shall be
bonded to each other and to ground.
The minimum bend radius for OSP optical fiber cable during installation shall
not be less than 20 times the cable diameter, and after installation shall
not be less than 15 times the cable diameter.
Optical Fiber Cable Testing
Testing of OSP optical fiber cabling shall be conducted according to ANSI/TIA/EIA-568-B.1.11.