Issue link: https://www.e-digitaleditions.com/i/1156106
October/November/December 2019 I 19 are only trustworthy up to about 35 feet (10.7 m) for 1080p signals. Their reliability for 4K is much shorter. Although the VGA analog signal standard was sun- setted several years ago and is officially obsolete, there are still many schools and businesses using VGA com- puters, laptops, and projectors. VGA cables typically can reach out to about 100 feet (30 m). For standard USB 2.0 cables, the range is approx- imately 16 feet (4.8 m), but it is reduced to only 10 feet (3.0 m) when used with USB 3.x devices. Signal extenders are available to extend all these signals over Category cable using a variety of technol- ogies. To accommodate today's high-bandwidth ultra- high-definition HDMI signals in an educational environ- ment, deploying extenders may be a good option because they reduce system complexity while fitting within a school's limited budget; simple control capabilities are an easy add-on. Using a system built on HDBaseT technology embraces that simplicity by allowing the integration of multiple signals on a single system and cable, covering the full range of AV technology. HDBaseT is an industry standard that provides high-definition HDMI extension 1. EXTENDING SIGNALS: KNOW WHEN PASSIVE AV CABLES ARE NOT ENOUGH Teachers in classrooms from kindergarten to college require AV systems that allow them to extend HDMI and USB signals from their desks to output devices located throughout the classroom. To accomplish this, some school administrators lean toward installing complex, professional AV systems with multiple touchscreen inputs and controls. Although these systems can meet the tech- nological needs of classroom AV equipment, using them effectively is often beyond the skill set of teachers and AV club members alike, thereby requiring professional installation, system set-up and maintenance by IT managers, and extensive training to operate. Classroom AV systems should not be complex. In an educational environment, a simpler system encourages student engagement, integrates easily into the learning setting, and upgrades for a longer life solution. A simple system is far more likely to accommodate the classroom infrastructure, school budgets, and end-user needs. When designing an AV system for a classroom setting, there are three keys to a positive user experience: 1. Extension for AV signals 2. Minimal components 3. Intuitive interface and easy controls HDMI ® 100 m 328 ft 12-15 m 40-50 ft VGA (Obsolete) 100 m 328 ft 30 m 100 ft USB 100 m 328 ft 50 m 164 ft 4.8 m 16 ft Below are recommended maximum lengths for different AV links, compared to maximum lengths using AV extenders: HDBaseT 100 m Extender over Category cable VGA with Extender over Category cable HDMI Cable VGA Cable USB 2.0 Cable USB 2.0 with Extender over Category cable USB 1.1 with Extender over Category cable Just as building infrastructure varies in age from school to school so too does the network infrastructure. Cat 5e, Cat 6, and Cat 6A UTP cabling can all be found in educational institutions today. In many school districts, passive cables have been the standard for AV systems for years, but passive cables will not provide adequate support for 21st century classroom AV signals. Most AV applications will require some form of signal extension (Figure 1). For example, HDMI cables are specified to be operational at lengths of 40 to 50 feet (approx. 12 to 15 meters). However, they FIGURE 1: Recommended maximum lengths for different AV links, compared to maximum lengths when using AV extenders.