Part 4:
Total Cable Certification: A Factory Guarantee + Field Testing
Introduction
There is no doubt that pre-terminated fiber helps cable installers to increase their job efficiency and reduce cost of installation. Since pre-terminated fiber cables are manufactured and tested to comply with various TIA/EIA standards, they offer good performance with “Factory Guarantee” directly out of the manufacturing facilities. Once these cables are installed in the LAN, SAN or datacenter environments, many uncontrollable factors can potentially affect their performance. Field testing is the only way to ensure that pre-terminated fiber is installed to meet the full certification requirements.
What is total cable certification for pre-terminated fiber?
Cable Installers need to be concerned about two aspects for certification; quality components and documentation after being installed. Total cable certification requires the installer to ensure: 1) Pre-terminated fiber is manufactured and tested to meet the “Factory Guarantee” standard requirements 2) Pre-terminated fiber is installed and certified to provide the performance as required by the network owner(s) for specific applications. To best determine the installation is correct – use both link loss testing (Tier1) and complete end to end (Tier 2) testing.
What does “Factory Guarantee” gives you?
Generally, pre-terminated fiber comes with guarantee of minimum optical performance that includes metrics such as:
- maximum attenuation,
- minimum effective bandwidth,
- and/or minimum guarantee bitrate
These parameter specifications defined whether the delivered fiber complies with the ANSI/TIA or TIA/EIA standards for various applications.
What impacts the performance of pre-terminated fiber?
Once the pre-terminated fiber leaves the factory, it is transported and stored in warehouse at a distributor before finally reaching the installation site. Many unknown factors can introduce contaminants to the pre-terminated fiber. For example, it may be examined by a customs officer that does not know how to handle the fiber carefully and cleanly. The fiber may also be stored improperly introducing bends or breaks that may damage the integrity of the cable.
Another threat to the performance of the pre-terminated fiber is that during installation, the fiber cable is being pulled and routed to fit into different casing or locations. The force exerted on the cable can inadvertently break the fiber inside or induce excessive loss over time due to micro- or macro-bending. In addition, when the pre-terminated fiber is uncapped during the installation, the technician or cable installer can also potentially contaminate or scratch the connectors without even knowing it.
What does Field Testing give you?
With the right test tools, proper cleaning practice and correct testing procedures, you can be sure that the fiber link being installed will meet or exceed the link loss and bandwidth requirements of the job as specified by the network owners and designed spec. An installer can also properly characterize the end-to-end fiber link even when multiple pre-terminated fibers are used. This is in particular important in campus environment, or in connector rich datacenter, where additional components (e.g. patch cords) are being used to create a long connectivity link between the ingress and egress of the network.
Summary
Pre-terminated fiber is an important innovation that offers the ease of installing high performance fiber network with reduced hassles in the installation process (e.g. no more field polishing and correct lengths). However, if you simply rely on the “factory guarantee” but ignore field testing aspect of certification, the fiber link installed can fail the industry performance standards and/or customer requirements. Both of which can be very costly if a callback is needed. Therefore, it is always important to complete the following steps to ensure total cable certification: 1) confirm the fiber trunks are as specified 2) clean and inspect the fiber before installation2) certify the fiber loss against the loss budget (tier 1 certification), and then 3) characterize the end-to-end fiber link (tier 2 certification) to complete the total certification process.
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