Seeking resolution

As AV content consumes greater bandwidth, the networks, equipment and cables required to store, switch and route are expected to keep pace. Steve Montgomery tracks the rise of fibre cable and optical switches.

Traditional copper cables and electronic equipment have served the industry well for many years. Now, however, fibre cables and optical switches are becoming more prevalent. This is opening up greater opportunities for installers as manufacturers offer enhanced ranges of equipment with greater throughput and a number of advantages, balanced by changes in the economics of large installations.

"With the ever increasing desire to display images at higher resolutions, we are using fibre extenders in the museum and visitors' entire sector primarily to extend signals from the control rooms to the gallery spaces," says Peter Barrett, leisure solutions director, Electrosonic. "Previously Cat 5 structure cabling provided the solution but can longer support the bandwidth and distances required for uncompressed high resolution signals."
Hagai Gefen, CEO of Gefen comments: “We see the large majority of fibre extenders and matrices in the broadcast, government and medical industries where high resolution data needs to travel between floors or even buildings. Fibre is impeccable in signal delivery although it is more expensive than industry standard cabling. These industries are willing to spend the money for EMI-protected transmissions that retain a 100% pure signal delivery.”

Copper cabling suffers from lack of capability to drive signals over long distances, brought about by the power requirements of fast switching electronics; a characteristic that is exacerbated by the increasing demands of high resolution images and increased frequency requirements. Brian Macauto, product manager at Magenta points out: "The vast majority of prestige installations cover large areas that need video to be transmitted over distances in excess of the 100 metres that is possible without repeaters using copper cabling; for example government sites, casinos, university campuses and cruise ships. The cost of fibre transmitters and receivers, even if they are initially more expensive than their copper counterparts can work out cheaper over long runs by eliminating the need for repeaters."

Fibre also allows far greater data rates to be achieved, which will permit data transfer of 40 Gbps in the near future, permitting dual link DVI and 4Kx2K resolutions in 3D to be transmitted without latency and compression.

Another set of issues that make fibre more attractive are the immunity to noise, crosstalk and data integrity. These ensure that content is transmitted and received without degradation or corruption and unaffected by close location of other electrical cables as well as ensuring that signal security remains at the highest level: it is not possible to eavesdrop on an optical transmission line without physically interrupting the cable itself.

"Fibre has considerable advantages over copper in its capability for extremely long distance extension and total security against ‘spying’ or compromising of the channel, is a very attractive proposition to, amongst others military and government applications." says Gergely Vida, CEO, Lightware. "Single fibre solutions are now relatively cost effective, they eliminate ground loops and hum effects, are immune to EMC noise."

For a long time, the cost of fibre installations and equipment has been perceived as too great for widespread use. This is however changing. There are two elements: the initial cost of the extension, switching and routing equipment which requires more specialised and hence higher cost components; and the cost of installing, terminating and testing fibre cabling; particularly over long and multi-user systems.

"Fibre cables are certainly a little more delicate than other more standard extension cables and care is needed to ensure the cabling is protected throughout the install," explains David Jones, UK general manager for Lightware. "This does make installing fibre more difficult and, to a degree, more dangerous to install, but, if due care is taken, the results tend to be far more reliable than that of copper.

“To terminate fibre is certainly more difficult and again, will therefore cost more to implement. However, there is always a higher cost for newer technologies that help to bring the market forward and fibre extension is no exception. In time, these products and skills will become standard practise and the costs will likely follow suit".

Peter Barrett concurs: "Handling and termination of fibre is more of a specialist activity that requires specialist knowledge and training. However, the products, terminations, tooling and connections have become more robust over the past few years, making it easier and more reliable. Fibre is more consistent than structured cable systems; we see quite a lot of variance in the performance of Cat5,6,7 cables and balums, depending on the manufacturer."
Installation of fibre cable on site has been a problem in the past as termination of cable required specialised tools and techniques. This is now becoming much simpler. Devan Cress, sales manager of manufacturer Broadata Communications is able to quantify the cost: "Fibre costs have been reduced drastically. Our partnership with Corning means that we are able to provide fibre cable terminations kits and training alongside our optical transmission equipment.

“There have been massive improvements over the past few years, to the point where it is now possible to terminate a fibre cable in two minutes with a small handheld device. This is a big change from the past when a termination might take an hour and cost €500."

Training and technical support is far more widespread as Jim Hayes, CEO of the Fiber Organisation points out: “We are the professional society of fibre optics, certifying the technicians who install and use it and have 250 training programs in 30 countries. So far over 32,000 technicians have successfully completed requirements for the FOA CFOT (Certified Fiber Optic Technician). Training is supported by a technical website on fibre with over 50 instructional videos on our YouTube channel.”
A further aspect is in the physical size and handling capability of fibre against copper. Fibre is attractive as it has a very small outside diameter and can fit in tight positions. With new fibre solutions including tactical and bend sensitive, fibre has become a robust solution for the future."
Physical strength and minimum bend radius are characteristics that have been worrying installers since the early days of fibre transmission. Devan Cress illustrates the point: "Specialist network cabling companies are widely used around the world to install all types of cables and they are generally getting to grips with fibre and can comfortably and safely install it, despite encountering problems in the early days."
Nick Mawer, marketing manager, Kramer verifies this: "Fibre optic cable does have to be handled more carefully than copper, but we have rental and staging companies using it, and they traditionally deal out tough punishment. Termination is the trickiest element and we only supply pre-terminated lengths. This is not to say that fibre cannot be terminated in the field, but that is a specialist skill."
External costs and the ability to rapidly and economically install spare cable capacity is an attractive advantage offered by fibre over copper. "Not only is the data carrying capacity of fibre cable much greater than copper, but they are much thinner and lighter so are consequently cheaper to install within the infrastructure of buildings," says Deven Cress.
"A 6 or 8 strand fibre jacket is the same size as a Cat6 cable so you can have much greater data capacity in the same physical space; a benefit that regularly allows installers to provide two and three times as much redundancy as they would otherwise have done. [This] allows security replacement and futureproofing within systems."
Manufacturers have been rapidly designing and releasing new families of equipment to take advantage of the falling component costs and increased demand for systems running over fibre backbones. One significant aspect is the use of SFP optical laser components that were originally designed for and are used in massive quantities in the telecommunication industries; allowing manufacturers to take advantage of the economies of scale offered with that technology. Features and functionality are being incorporated by individual vendors to differentiate their ranges. Common to most is the ability to automatically manage EDID and handle data encryption and security; key features in audiovisual installations operating with commercial content.
Technology advance is rapid in the fibre world. Major equipment vendors have offered fibre extenders for some time to cope with all levels and flavours of video and audio formats, and including the associated communication and handshaking protocols that ensure the components work transparently within systems. More recently fibre matrices have become available that enable switching and routing of large numbers of sources and displays from a central point over data links up to several kilometres in length.

Gefen’s recently launched FM-1500 series of DVI extenders delivers video resolution up to1920x1200/1080p together with RS-232 control over the same cable. Transmitting up to 300 meters over a single strand of multi-mode fibre and 12 kilometres using single cables.

Two transceivers are connected at the local and remote locations, linked by a single strand of fibre optic cable terminated in SC connectors. Virtual EDID programming ensures a constant synching of the video source to the display. The GefenPRO 3GSDI Fibre Optic Extender Short Range offers another option for integrators that need to extend 3G SDI up to 500 meters. It uses small, dongle-type sender and receiver units to extend a source using 3GSDI to its display over one single-mode fibre optic cable terminated in ST connectors.

Magenta Compact Format CF range provides a small form factor receiver that can easily be concealed behind display wall mounts. An 18-module card cage allows transmitters to be housed together with redundant power supplies to provide a neat and easy method of installation. The system also offers its own extended touch screen control programme that enhances third-party controllers with addition monitoring features such as power level, equipment temperature and other system-level parameters.

Light Bridge technology from Broadata is a modular format plug-in range to provide convenience and efficiency in multi-signal format systems, “Building the converter in the box BCI has simplified installation and reduced the points of failure,” explains Devan Cress, “It means it will allow HD-SDI, S-video, Composite video, HDMI, DVI, or RGB in over 100 possible combinations and transport it over fibre to HDMI or DVI with no additional converters. Future proofing is assumed by simply changing the transceiver module to another signal format.”

Perhaps the latest development trend is to integrate as many signals in one fibre as possible: various forms of video, multichannel audio, together with USB, RS232 and IR control signals.
This is achievable over fibre using multiplexing techniques. Gergely Vida: “In the past, a single core needed to be used per signal type. So, for video, audio and RS232 you would need a minimum of 3 cores. Lightware has developed our ‘Single Fibre Technology’ so that video and audio extension can be achieved over one fibre core. One real feature of this technology is that HDCP and EDID handshaking is done over the same fibre using a 6 wavelength CWDM system. Our DP-OPT-TX100 and RX100 products even support Displayport. We don’t compress signals so as to maintain the video quality and lip-sync in the overall AV system.”

Kramer has also added new products to their line-up, including the 670 series; a range of products designed to send DVI, HDMI or VGA up to a mile over a single multimode fibre, and options for HD-SDI transmission, a format widely used in the broadcast industry.

Fibre cabling has often been included in new installations alongside copper, to allow for future upgrades and futureproofing. Until recently it has been left ‘dark’. However with recent cost reductions and simplification in installation and equipment setup, together with the usability of equipment, particularly new matrices and extensive data bandwidth capability, fibre is becoming more common. And, it will continue to do so into the future, displacing copper as the primary communications technology in most professional audiovisual installations.

This will take some time, perhaps five years or more and as Peter Barrett points out: “We will see more fibre-enabled products for the distribution of signals both on a point to point and multiplexed basis. However, on a cautionary note, we should not always get carried away with the use of fibre and the latest and greatest. We should apply the technology that is right for the application and in many instances copper still provides the most reliable and cost effective option.”

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