Home' RTCA Documents for Review : DO-230H FRAC Contents 261
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Identify all wire and cable at terminations and at every junction box. Cable labeling should comply
with TIA specifications, and all labels should use indelible markings made on waterproof media.
The communication system should provide, as a minimum, Class II (UL Class AA or equivalent)
Line Supervision. Class I (DES or equivalent) Line Supervisions should be provided for data links
that are expected to traverse uncontrolled areas.
Legacy ISSA configurations include control panels (either stand-alone or networked to a host
computer via RS485) to the various portals (addressed with Wiegand protocol card readers) directly
wired to specific portal functions (i.e., door “open/shut” sensors, “request to exit” switches, and
Standard project management practice should be employed to ensure that all work is planned and
implemented to install the system with minimal disruption to ongoing operations (i.e., completed
system layouts and installation plans are well-coordinated with all providers and stakeholders and
equipment, conduit runs, power considerations and so on are located, identified, charted and
circulated to all interested parties before installation begins.
Establish schedules in specs by editing the specification drawings on the job to as-built, by noting
the following in red as work is done (or before it starts):
o Outlet numbers
o Outlet locations changed as a result of architectural coordination
o Cable manufacturer and model (especially various backbones)
o Cable capacity mix (whether 100 pair in one sheath, 2 x 50 or 4 x 25pair)
o Fiber and Cat 5e backbone cable run length (from sheath markings)
o Patch panel or fiber frame make, model and capacity (for each panel, if each different)
o Fill out distribution frame record books in pencil, including service and jumper details as
soon as installed.
Fiber Optic Backbone Cabling
Optical fiber is available in two forms: single-mode fiber (SMF) and multi-mode fiber (MMF). Either type
may be manufactured as loose buffered cable, tight buffered cable, armored cable, aerial cable, etc. to suite
a variety of applications and performance requirements.
In SMF, light follows a single path through the fiber while in MMF it takes multiple paths resulting in
differential mode delay (DMD). SMF is used for long distance communication and MMF is used for
distances of less than 300 m. SMF has a narrower core (8.3 μm) which requires a more precise termination
and connection method. MMF has a wider core (50 or 62.5 μm). The advantage of MMF is that it can be
driven by low cost VCSEL lasers for short distances, and multimode connector are less expensive and easier
to terminate reliably in the field. The advantage of SMF is that it can work over longer distances.
To distinguish SMF from MMF cables, SMF cables have a yellow outer sheath, while MMF cables have
either orange (OM1 & OM2) or aqua (OM3 & OM4) outer sheaths. These colors only indicate the type of
fiber cabling, not the performance of the fiber.
Backbone cabling is also used to interconnect entrance facilities (such as Telco demarcation points) to the
main cross-connect. Maximum allowable backbone fiber distances vary between 300 m and 3000 m,
depending upon the cable type and use.
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