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PRE-TERMINATED CABLING
Consider what has happened to that MPO trunk since the
factory test? At the very least, it’s been capped, coiled,
packed, weighed, dispatched and transported. Then
received, unpacked, uncoiled, data-checked and installed. All
handling, all gentle, and respectful of the fact that it is 12
or 24 cores of glass in a flexible wrapper, naturally. And in
the event that this trunk proves faulty, the manufacturer will
provide a free replacement and pay for the installation. But
I bet they won’t cover any late completion penalties, or loss
of earnings due to project overruns.
Surely it makes some sense to view an MPO trunk as
any other incoming material, and give it a quick check for
continuity before installation? The actual testing takes less
than 10 seconds per trunk, but can save a serious heartache
later on. Before we get to the actual testing though, we need
to address the plug and play claim.
Plug and play
Anyone who has spent any time at all with MPO technology
will be aware that this is actually ‘inspect clean inspect
(Repeat as required) plug and play. In this area, we face a
few challenges: in portable camera-based end-face inspection
tools, there’s currently no offering which enables a user
to view a complete 12-fibre connector in a single image.
Three or at best four fibre cores can be viewed at any one
time. Likewise, the industry standard which covers end-face
condition, IEC-61300-3-35, is not generally applicable to MPO
end-faces, as it was written around single-fibre connectors.
Automated end-face analysers fair little or no better as
they’re presented with too many anomalies to deal with.
A word about MPO end-faces for those who are
accustomed to LC or SC connectors: while a clean LC ferrule
end-face will resemble a dartboard on a white wall, when
viewed through an end-face camera, an MPO connector is
plastic and the end-face more closely resembles the surface
of the moon, being bumpy, cratered and pitted, with the line
of fibre cores extending across the end-face. To those of us
paranoid about contamination, each surface imperfection is a
potential dirt trap that needs to be cleaned and inspected.
Cleaning