FIGURE 7: TIA-862-B recommends that a plug-ended horizontal cable link is terminated from an HCP (such as a zone
enclosure) or work area outlet. ANSI/BICSI-005 and 007 standards recognize this option or as a direct connection.
from the TR or the HCP as shown in Figure 7.
For TIA, the preferred horizontal cabling topology
is to have a TO and a patch cord at the device end or
where deemed necessary an MPTL directly from an HCP
or zone box. Today, connectivity manufacturers have
developed modular field-terminated plugs that are higher
performing and much more durable and robust than
previous RJ45 field terminated plugs. System warranties
can also be extended as major equipment manufacturers
have developed methods to test this configuration.
When remote powering current loads are present,
it is important that critical connecting hardware
contact mating surfaces are not damaged by the arc that
occurs when modular plugs and outlets are unmated or
disengaged. While the current level associated with this
arc poses no risk to humans, arcing creates an electrical
breakdown of gases in the surrounding environment
that results in erosion and pitting damage on the plated
contact surface at the arcing location. When the erosion
Location of Arc During Unmating Cycle Final Seated Contact Position
24 I ICT TODAY
Consolidation Point /HCP
(Recommended) Plug on the horizontal
cable
When digital IP security cameras were introduced,
security integrators were terminating RJ45 plugs onto
the cable and connecting directly into the cameras when
an outlet and patch cord was not feasible to deploy at
the camera location. Today, ANSI/BICSI-005 and ANSI/
BICSI-007 (see Figure 5) both refer to this as a direct
connection method at the device end and is allowed in
certain circumstances. Another reason for enabling this
topology includes the fact that not all outlets and patch
cords are plenum rated as required by code, and the use
of a plug attached to a plenum-rated cable eliminates
these concerns.
ANSI/TIA-568.2-D recognizes a similar method
referred to as a modular plug terminated link (MPTL)
that is an option for connecting devices where it is
deemed impractical or unsafe to deploy a TO and
equipment cord (see Figure 6). The difference between
the TIA and BICSI standards is that BICSI approves a plug
to be attached directly to the horizontal cabling either
FIGURE 8: In this connecting hardware example, the location of the arc during unmating under load occurs well
away from the final seated contact position on both the jack and the plug for superior PoE reliability.