Amid pervasive talk about promises of information economy, it’s easy to overlook logistical challenges of delivering necessary infrastructure to ensure everyone who wants connectivity is connected—regardless of where they live. Projected growth in customer demand for bandwidth will go wanting without connectivity, and real challenge for fully realized networks is to create connections despite very real physical and economic obstacles presented by today’s modern cities. The rewards for providing these connections are likelihood of recouping previous investments in fiber-optics network core/backbone—and establishing customer reliance on high-bandwidth networks for continued economic growth.

At one point, many telecommunications industry leaders and technology observers dreamed of all-fiber networks. But this vision is impractical for several reasons. The process of laying fiber in cities is time-consuming and often prohibitively expensive. Ongoing preservation and restoration of fiber-optic systems in event of accidental disruptions or natural disasters is also time-consuming and technically challenging, as service providers must address concerns of bandwidth dependent customers frustrated with every hour of lost network access.

That having been said, all-optical fiber-optic networks—with their high-bandwidth capacities—are promising. Still, a world complete with fiber connections for all is decades from reality.

Deciding how best to complete high-bandwidth connections across networks is one of great quandaries of information age, and choosing which technologies to deploy to complete network connections will depend on costs and reliability(1) A combination of high-capacity access technologies provides most cost efficient and reliable solutions for addressing both primary connections and backhaul. For all-optical networks, fiber optics and optical wireless solutions are only two technology choices.

(1) Source: Free Space Optics, Merrill Lynch Global Securities and Economics Group, 15 May 2001

Parallel Histories

It may seem to telecommunications carriers and industry analysts that FSO technology only recently appeared, like a beam of light, to optical communications landscape. But FSO is only new in one respect: as a market proven technology for optical wireless solutions that provide customer connectivity in private and public networks spanning more than 60 countries.

FSO technology itself is older than fiber optics. Technically, optical communications includes all forms of communications using light, including mirror signals and lighthouses, offering a rich and storied history.

The electrically powered optical technologies referred to by term “optical” or “electro-optical” began with introduction of laser in 1960, which enabled transmission of digital information as pulses of light.

FREE-SPACE OPTICS

Recent developments in FSO technology target telecommunications improvements for Metropolitan Area Networks (MANs), but technology has its roots in government applications dating back to World War I when military units and covert agencies needed secure communication systems that did not require cable and could withstand intentional interference, also known as “radio jamming”. Portability of these early FSO devices was a hallmark and made them particularly valuable to military personnel who needed secure communications equipment that was simple to set up, transmit information and move from location to location. Additional optical communications developments occurred during World War II, and post-war economic restructuring led to further telecommunications technology progress. While electronics innovations such as transistor and integrated circuits enabled post-war telecommunications progress, laser’s launching of electro-optical communication fueled research and development of advanced optical communications using only medium for laser transmission available then to military and aerospace industry physicists: atmosphere, or “free space,” hence term free-space optics. Research and application of free-space optics continues to thrive in aerospace industry to this day for applications beyond commercial and private telecommunications networks. Today’s commercially deployed optical wireless solutions are result of a culmination of FSO technology advancements.

FIBER OPTICS

After 1970, introduction of fiber-optic cable as optical transmitter—along with establishment of digital technology—combined to usher in a worldwide telecommunications revolution. Key among fiber’s attributes is its immunity to electrical interference (no electricity is run through fibers, so fiber signals do not interfere with each other); therefore, fiber can be run in areas without regard to interference from electrical equipment. Other benefits of fiber are:

• Security. It is resistant to taps and doesn’t emit electromagnetic signals.

• Compact size. Less duct space is required for these hair-strand sized fibers.

• High-bandwidth capabilities and low attenuation. Less fading or weakening of signals occur over long distances, which means fewer amplifiers are needed to boost optical signals.

Given these advantages, fiber-optic cable held promise of revolutionizing telecommunications sector, which was eager to build initial fiber networks.2 The first practical fiber systems were deployed by telephone industry in 1977 and consisted of multimode fiber. Single-mode fiber, a more recent development, was first installed by MCI in a long-haul network system that went into service in 1983.3 The result of fiber-optic cable deployment is an extensive network of fiber crisscrossing land. During 1990s, telecommunications network capacities grew nearly 10 times as much as traffic itself, with most of bandwidth concentrated in dark fibers along network backbone often inaccessible to end-user.5 The massive investment to put optical capacity in long-haul telecommunications network backbone looks relatively simple compared with today’s metropolitan network challenges.

Beginning in 2000, carriers intensified their focus to building fiber-optic cable connections between United States’ 25 largest metropolitan areas to nation’s long haul backbone networks. This network gap is often called “last mile,” where only 7 percent to 10 percent of end-users have access to fiber. “Routes in cities typically run to incumbent telephone company central offices and carrier hotels, which often are clustered together in same areas, frequently near AT&T’s switches.

Components of Digital Signage The components needed for a digital signage system include:

An authoring console, equipped with content management software, allowing definition of content in a variety of playback formats.

A server, to which finished content is uploaded and from where it is distributed to different displays in network.

A distribution infrastructure, consisting of a data network or fiber optic or CAT5 cable, which broadcasts media from server to displays.

Digital signage displays, which can be plasma displays, LCD monitors, CRT monitors, or kiosk stations.

Benefits of Digital Signage Digital signs have already brought significant benefits to businesses and media vendors alike:

Attention grabbing advertising A digital sign brings innovation and movement to previously static media locations, and has power to get customers' attention, making it a particularly effective form of advertising.

Real-time advertising and information Digital signage allows advertising and information to be updated on fly from one remote authoring station and broadcast immediately to audiences regardless of location.

Relevant audiences With digital signage, advertising focuses on best potential customer: an existing one. Supermarkets have already found that current customers are more likely to purchase products advertised on their digital signs. Cost savings Every time digital signage users change their message or campaign, they save on printing costs and processing time. Profit center opportunities Businesses can create instant profit centers by selling advertising time on their digital signs to customers or suppliers.

DIGITAL SIGNAGE Uses of Digital Signage It is not surprising that, with all benefits of digital signage, there are so many uses for it worldwide. They include: Advertising networks In-store advertising Interactive kiosks Tradeshow displays Corporate identity branding Electronic menus and lobby displays Branch office communication Campus bulletin boards Community bulletin boards Arrival and departure schedules Franchise communication systems Emergency announcement systems Corporate communication systems Back office employee training

Digital Signage Distribution Technology: “What Lies Beneath” When considering a digital signage project, users usually focus on display types and content management software. For integrator, however, there is an important component that user rarely considers: distribution technology and platform. This infrastructure transmits digital video and audio from server to appropriate displays, and is a key contributor to actual digital signage performance. In addition, as connecting component for all displays, distribution technology can be a significant part of project budget. That’s why choosing correct distribution technology is vital in ensuring a successful digital signage installation. Options for Digital Signage Distribution

There are three main options for digital signage distribution:

Data network Fiber-optic cable CAT5 cable

In this paper, these options will be presented together with core considerations in choosing a distribution technology:

Cost Performance Existing infrastructure

Digital Signage Distribution Options: Platforms & Combinations

Each platform has its own benefits and drawbacks. When harnessing more than one platform. There are a number of interesting combinations as discussed below.

Data Network Platform A data network platform uses a computer network infrastructure in order to transmit content in form of compressed multi-media files (such as MPEG files) from management station to central server and from there to computer connected to display device. The central server handles distribution to multiple displays, and display-end computer decompresses file for display on display device. Alternatively, if only one display is required, network can transmit compressed file directly from management station to display-end computer, which then decompresses and displays file.

Benefits & Drawbacks The advisability of data networks depends largely on existing infrastructure. If there is an existing computer network infrastructure, using a data network platform for digital signage can save costs significantly. However, if no computer network already exists, need to implement such an infrastructure will increase costs considerably.

An additional cost related to data networks is caused by need for display devices to be connected to local computers or equipped with embedded CPUs, resulting in extra investment in hardware, an important factor when costing project as a whole.

In addition, from a performance standpoint, using a data network platform has several disadvantages. A data network platform limits user to compression technologies available on market today, technologies that significantly downgrade quality of multimedia content and displays’ dependence on network is another major consideration for 24x7 locales that cannot tolerate display downtime.

Fiber Optic Extenders Fiber optic cable is a transmission medium favored for applications that need high bandwidth, long distances, and complete immunity to electrical interference. That makes it ideal for digital signage, which requires high resolution and transmission over long distances. Unlike network platforms, fiber optic cable does not require CPUs or special software at display end. All that is required is a transmitter and receiving unit for each display.