The IEC recently published the first standard for field testing of MPO installations. IEC 61280-4-5 fills a gap in standards by providing clear guidance for how to test MPO systems of various configurations. For some time, VIAVI has made clear statements that existing standards such as IEC 61280-4-1 and 4-2 apply to simplex and duplex fiber testing but cannot be easily adapted to testing MPO systems which have their own unique characteristics. VIAVI welcomes this standard, as it provides specific instructions on how to perform loss/length/polarity tests on MPO links that are pinned or unpinned (as well as unpinned channels) with dedicated MPO optical loss test sets such as the VIAVI SmartClass Fiber MPOLx family. This new standard also covers the inspection of MPO end-faces as well as using OTDRs equipped with optical switches to test and certify MPO systems.

For pinned power meters such as the MPOLP-85, this new standard advises that the Reference Test Method (RTM) for testing pinned links is the one cord method, while for testing unpinned links the RTM defined calls for the use of gender-neutral cords. Gender-neutral cords are those that allow the connector to be changed from pinned to unpinned (or from unpinned to pinned) in the field. Gender-neutral cords allow for a one-cord reference to be performed with an unpinned test cord connection to the power meter. After the reference is set, the launch cord is changed to pinned for connection to the cabling under test.  There are a variety of these types of cords/connectors available on the market from leading connectivity vendors (see: this and this). In addition to the one cord method, the standard also defines an adapter-cord method as an Alternative Test Methods (ATM) for testing unpinned links with a pinned power meter. This method can be used when the RTM is impractical, or another approach is desired. The adapter-cord method requires a pinned-to-pinned adapter cord be used on the launch cord after the reference is set to facilitate connectivity to the unpinned system.

This comprehensive standard covers several other important topics related to field testing MPO systems, including verification of test cords and measurement uncertainty considerations. It is quite important to note that MPO connectivity has a much higher level of uncertainty than simplex or duplex connectivity. As such it is critically important to minimize these uncertainties as much as possible to ensure accurate field loss measurements of MPO systems.

Deployment of MPO connectivity is only increasing. Whether for high speed links using parallel optic technology or for port density, MPO is here to stay. Being able to quickly and reliably test and certify these new installations with modern dedicated MPO test instruments is becoming increasingly important. The new standard from IEC is an important step in helping the industry achieve this goal.


Ed Gastle has more than 30 years of experience in the telecommunications industry with a focus on test and measurement of all types of infrastructure and networks. His experience ranges from structured cabling to LAN/WAN data networking to optical systems. Much of his career has been focused on teaching installers, technicians and engineers how to become more effective at testing and troubleshooting telecommunication networks. His current role is global product manager for Data Center and Enterprise test solutions at VIAVI Solutions. In this role Ed participates in standards bodies such as IEC and TIA.

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