Calrec SUMMA, Руководство по установке

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50 SUMMA
Networked Audio Production System
Connection Information
FIBRE SFP CONNECTIVITY
Optical SFP modules for fibre
connectivity can be used for console
to processing core, router to router,
and router to I/O connections.
Fibre connectivity is required when the
cable run between units exceeds the 90 m
maximum permissible length for Cat5e/
Cat6 copper cabling. Fibre can also be
used for shorter runs if it is simply the
preferred medium.
Note, this section only concerns fibre
connections made via SFPs. Like all I/O
boxes, MADI units have pluggable SFPs
for their Hydra2 connections to routers,
but they also have fibre connectors that
pass the actual MADI audio format in and
out of the system. The MADI I/O format
fibre connectors are of a fixed type which
has no relation to SFP choice. Various
MADI I/O boxes are available to provide
different types of MADI fibre interface.
Please refer to the Hydra2 installation
manual for more details on MADI I/O
options.
SinglemodevsMultimode
The core within multimode fibre is
relatively thick when compared to
singlemode. Light travels through
multimode fibre at multiple angles,
‘bouncing’ off the sides of the core as it
travels, taking multiple paths or ‘modes’ of
varying length from one end to the other,
resulting in pulses being lengthened as
they travel. Singlemode fibre has a very
fine core and light travels in a single, direct
path from one end to the other without
affecting pulse length. The result is that
singlemode fibre has a higher bandwidth
capacity and, importantly, low signal
loss allowing much greater distances to
be achieved. Light can be transmitted
into multimode fibre using LEDs or low
powered lasers whilst singlemode requires
a higher powered laser.
Calrec recommend the use of singlemode
fibre whenever possible in order to
maximise the flexibility in the location of
hardware and maintain uniformity across
the system by using a single type. If a
multimode infrastructure is in place, fibre
length, the number of inter-connects
and equipment location become more
important.
SFP modules are available for both
singlemode and multimode fibre types.
It is important to select the correct
SFP for the type of fibre being used in
the installation. If using a mixture of
singlemode and multimode fibre, it is
important to ensure the correct SFPs are
matched to the correct fibre type.
Identification
The release button/handles of fibre SFPs
are colour coded - Blue for singlemode,
Black for multimode. Blue LC connectors,
as shown here, should be used to
terminate singlemode fibre and beige
coloured connectors for multimode.
DuplexConnectors/Terminations
Standard Calrec fibre SFPs, both
multimode and singlemode, use duplex
LC connectors. The duplex termination
requires two fibres per connection, one
is a send path, the other is a receive path.
When terminating the fibre, the send from
one end should connect to the receive of
the other and therefore they ‘cross-over’,
terminated A to B and B to A.
SingleStrand,Bi-DirectionalSFPs
To reduce the amount of fibre, Calrec
can supply singlemode SFPs that send
and receive over a single, or simplex LC
connector. In order to be able to pass
data in both directions over a single
strand, the light travelling in one direction
needs to be of a different wavelength to
the light travelling in the other direction.
Therefore, bi-directional SFPs come as
either type A or type B (as indicated by
an A or B at the end of the model number)
and they need to be paired up; a fibre
should connect between a type A and a
type B, and not between two bi-directional
SFPs of the same type/wavelength. The
units are colour coded to aid identification
between A types & B types.
SFPFibreSpecifications
Specifications are shown in the table
to the right. The maximum distances
shown here assume a single point-to-
point connection with no intermediary
interconnections. Losses should be
measured across the total signal path
including interconnects - between points
of SFP transceiver connection. Losses
need to be less than the optical power
budget of the SFP transceivers being
used.
DUPLEX LC FIBRES CORRECTLY TERMINATED A TO B & B TO A
BI-DIRECTIONAL LC FIBRE CORRECTLY CONNECTED, TYPE A TO TYPE B
A
A B
B
A B