General Overview - Video over CAT5 in the dynamic signage market


Dynamic signage is clearly a growth market. In the retail environment it can run the gamut of applications. News and information content designed to entertain customers while standing online at a grocery store, advertising in an elevator, and menu board content in fast food restaurants are examples of retail virtual signage applications being run over UTP (Unshielded Twisted Pair), also known as CAT5 cable.

The advent of powerful computers, sophisticated video content streams, teamed with powerful updating tools, multi tasking video cards and large colorful plasma displays allow virtual signage applications to effectively reach a broad market. With the downward pressure on the cost of this technology, we have now reached a point where  financial models for virtual signage have become valid. These applications are transitioning from a wish to a reality.

        21st century signage, supported by 19th and 20th century infrastructure

The best retail signage message in the world, delivered in the best-produced video vehicle, managed and presented over the finest computer and signage technology available and displayed on the largest, highest-quality displays is totally worthless if you can’t get the video to the display!

In the real world, buildings that were constructed as late as the 1980’s, generally were not designed with the wiring requirements of the information age in mind. Wiring raceways, conduits and snake trays are generally jammed. Cabling that will support the high resolution video (minimally VGA or XGA),  called for in most video signage applications (for example, a coaxial cable terminated onto 5 BNC connectors or a standard VGA cable terminating on a 15 pin connector), simply won’t go through the conduits in most existing structures. Beyond the video content that must be delivered, there is generally a control line (RS232 cable) that must also go from the computer to the display. This creates a dilemma for the system installer.

The choices

Since building codes generally require that VGA cable and RS232 control lines go through conduits or snake trays, and these pipes and trays are frequently jammed, the installer is left with some difficult choices to make:

1: Install new larger conduits or trays. (Usually a very costly proposition.)

2: If there is some room in the conduits, the 15-pin connector can be cut off of one end of the VGA cable, and hopefully the cable can be snaked through. Then, if you reach your destination, you must re-terminate the VGA cable with an aftermarket 15-pin connector.  The quality of the field termination may not be up to the factory standards and video quality may suffer. Certainly it is much more expensive to pull heavy gauge wire like a VGA cable and costly and time consuming to re-terminate.

3: Find a more installation-friendly medium to deliver the XGA video and/or the serial control to the displays.

Alternative delivery options:

1: Wireless Technology certainly fits the criteria for not jamming up already-choked conduits and raceways. The issues with wireless are: bandwidth vs. cost, reliability and performance.  The bandwidth required for wireless transportation of real-time, full-motion XGA video and full-modem serial control is daunting.  Current practical (affordable) wireless solutions are simply not capable of providing real-time, uncompressed video transport.  On-site signal density directly affects signal latency.  The more wireless links there are competing for over-the-air bandwidth, the more the compression artifacts and latency become pronounced.  If the required bandwidth can be delivered at all, it certainly can’t be delivered in a cost-effective way. 

2: Ethernet on UTP will cut down the size of the wire running through the trays and conduits. It also eliminates the need for a long serial control line since the controlling computer is next to the display. The problems with this solution are considerable.  The cost of placing a computer at each display, plus the ongoing licensing cost for the software at each display is usually prohibitive. The limited reach of 300’ from the server/ hub to any network computer (hence each display) limits the “reach” of this type of application. More importantly, the practicality and serviceability of remotely placing computers with the displays generally far outweighs the advantages of this method.

3: Delivery Over IP  would suffer from all of the problems associated with Ethernet, plus the inherent reliability problems with streaming video over IP simply is not acceptable in an environment where smooth delivery of content is absolutely critical.

What is the answer?

The answer is video and serial control distribution over dedicated UTP runs. The advantages are that UTP is smaller, easier and less expensive to pull than VGA or coaxial cable. Most commercial buildings today have a complete matrix infrastructure of UTP cable already in place. UTP does not need to be run through the conduits or trays in most municipalities. In fact, it can usually be run right over ceiling tiles and under carpets. In addition, the cost of the wire is far less than that of any of the other alternatives. Since the introduction of the MultiViewä Series from Magenta Research the quality issues of XGA video delivered over UTP have been eliminated. The MultiView XR-2000 can deliver full motion, real-time WUXGA video at 2,000 feet (610m).  Even at this distance, the video quality makes it difficult, if not impossible, to differentiate between the remote and the local display.  Magenta’s MultiView Series is, unlike most other systems on the market today, designed specifically for the signage market. That can be seen in both the range and form factor of our systems. The industry-leading transmission distance and nearly limitless distribution capability make the MultiView Series the “integrators’ choice” for installation in signage applications.