Calrec ARGO, Инструкция по установке и техническому обслуживанию

Страница: 49 / 92

49
IP network connections and
control surface to processing core
connections made via copper SFP
modules require shielded F/UTP
Category 5e or Category 6 cables with
shielded RJ45 mating connectors.
Calrec do not supply these cables as it is
often preferable to terminate them after
they have been run through cable ducting
to avoid damaging the terminations, and
to be able to cut them to the precise
length required.
Shielded cables and connectors
Shielded cabling and connectors are
required in order to meet EMC (Electro-
magnetic compatibility) standards to
comply with the radiated emission limits
set in the standard EN55022, as well as
to guarantee performance in electrically
noisy environments.
F/UTP Cat5e/Cat6 cable has an overall
foil shield around the conductor cores.
Shielded RJ45 connector plugs have a
metallic shield around them which should
be clamped / bonded to the shield within
the cable. The shield on the connector
mates with the chassis of the RJ45
socket that it is plugged into, providing an
earth to the cable shield.
The method of attaching the connector
shield to the cable shield can vary. Please
refer to the connector manufacturer’s
information for further guidance.
COPPER SFP CONNECTIVITY
SHIELDED RJ45 CONNECTOR
Conductive connector mating
screen clamped / bonded to
cable shield
Maximum cable length
The maximum length of Cat5e/Cat6
cables is 90m / 295ft. This is the
absolute maximum and needs to include
any patch points and cables that may
be in the path. If a run between devices
exceeds the maximum recommended
distance for copper cabling, fibre and
optical SFPs should be used instead.
Cable routing considerations
The layout and twist rate of the data cores
within Cat5e/Cat6 cables are integral
to their performance at high speed over
distance. Poor installation practise can
seriously impact upon this. The following
are general good rules of practise,
please refer to the cable manufacturer’s
information for comprehensive installation
rules.
When running Cat5e / Cat6 network
cabling, it is important to avoid kinking
the cable. Kinks can seriously impair
performance. Cable manufacturers
advise that kinked cables should be
discarded and replaced as the damage
caused cannot be addressed simply by
straightening the outer appearance.
Cables should not be bent in tight angles,
this too can seriously impair performance.
Please refer to the cable manufacturer’s
specification on minimum bend radii.
Excessive pulling force when routing
cables can deform the twist rate of the
cable cores, causing irreparable damage.
Cable manufacturers specify a maximum
pulling tension.
Cable-ties should not be over-tightened
as this also deforms the internal structure
of the cable. Cable ties should be tight
enough only to support the cable weight
but not so tight as to cause any visible
deformation to the cable’s outer jacket.
Crimp points
Cable outer jacket
Strain relief
STRAIN RELIEVED RJ45 TERMINATION
Large, heavy bundles of cables can
be difficult to support using cable-ties
without causing damage. 'Velcro' style
hook-and-loop cable straps can be a
good alternative to plastic cable-ties.
Whilst neatly bundled parallel cable runs
are tidy and aesthetically pleasing, they
decrease cross-talk immunity which
can impact on performance. Avoid neat
bundling of network cables over any kind
of distance - the majority of a cables
length is normally unseen, running under
floor or through ducting where they
should be loosely laid rather than neatly
bundled.
Termination - strain relief
Poor termination and lack of strain relief
is one of the most common causes of
high speed network cable problems.
To properly strain relief the data cores,
the outer jacket of the cable should be
inserted into the RJ45 housing and held
in place once crimped by the strain-relief
point, as shown in the following diagram.
This also maintains the integrity of the
twist rate and shield into the termination,
and therefore the full length of the cable
conforms to its’ intended specification.
• Note, this is a simplified
diagram that does not
include the shield.