Black Box Explains...Digital Visual Interface (DVI) and other digital display interfaces.
There are three main types of digital video interfaces: P&D, DFP, and DVI. P&D (Plug & Display, also known as EVC), the earliest of these technologies, supports both digital and... more/see it nowanalog RGB connections and is now used primarily on projectors. DFP (Digital Flat-Panel Port) was the first digital-only connector on displays and graphics cards; it’s being phased out.
There are different types of DVI connectors: DVI-D, DVI-I, DVI-A, DFP, and EVC.
DVI-D is a digital-only connector. DVI-I supports both digital and analog RGB connections. Some manufacturers are offering the DVI-I connector type on their products instead of separate analog and digital connectors. DVI-A is used to carry an analog DVI signal to a VGA device, such as a display. DFP, like DVI-D, was an early digital-only connector used on some displays; it’s being phased out. EVC (also known as P&D) is similar to DVI-I only it’s slightly larger in size. It also handles digital and analog connections, and it’s used primarily on projectors.
All these standards are based on transition-minimized differential signaling (TMDS). In a typical single-line digital signal, voltage is raised to a high level and decreased to a low level to create transitions that convey data. TMDS uses a pair of signal wires to minimize the number of transitions needed to transfer data. When one wire goes to a high-voltage state, the other goes to a low-voltage state. This balance increases the data-transfer rate and improves accuracy. collapse
Black Box Explains...Wireless Ethernet standards.
The precursor to 802.11b, IEEE 802.11 was introduced in 1997. It was a beginning, but 802.11 only supported speeds up to 2 Mbps. And it supported two entirely different... more/see it nowmethods of encodingFrequency Hopping Spread Spectrum (FHSS) and Direct Sequence Spread Spectrum (DSSS). This led to confusion and incompatibility between different vendors equipment.
802.11b is comfortably established as the most popular wireless standard. With the IEEE 802.11b Ethernet standard, wireless is fast, easy, and affordable. Wireless devices from all vendors work together seamlessly. 802.11b is a perfect example of a technology that has become both sophisticated and standardized enough to really make life simpler for its users.
The 802.11b extension of the original 802.11 standard boosts wireless throughput from 2 Mbps all the way up to 11 Mbps. 802.11b can transmit up to 200 feet under good conditions, although this distance may be reduced considerably by the presence of obstacles such as walls.
This standard uses DSSS. With DSSS, each bit transmitted is encoded and the encoded bits are sent in parallel across an entire range of frequencies. The code used in a transmission is known only to the sending and receiving stations. By transmitting identical signals across the entire range of frequencies, DSSS helps to reduce interference and makes it possible to recover lost data without retransmission.
The 802.11a wireless Ethernet standard is new on the scene. It uses a different band than 802.11b—the 5.8-GHz band called U-NII (Unlicensed National Information Infrastructure) in the United States. Because the U-NII band has a higher frequency and a larger bandwidth allotment than the 2.4-GHz band, the 802.11a standard achieves speeds of up to 54 Mbps. However, its more limited in range than 802.11b. It uses an orthogonal frequency-division multiplexing (OFDM) encoding scheme rather than FHSS or DSSS.
802.11g is an extension of 802.11b and operates in the same 2.4-GHz band as 802.11b. It brings data rates up to 54 Mbps using OFDM technology.
Because it's actually an extension of 802.11b, 802.11g is backward-compatible with 802.11b—an 802.11b device can interface directly with an 802.11g access point. However, because 802.11g also runs on the same three channels as 802.11b, it can crowd already busy frequencies.
Super G® is a subset of 802.11g and is a proprietary extension of the 802.11g standard that doubles throughput to 108 Mbps. Super G is not an IEEE approved standard. If you use it, you should use devices from one vendor to ensure compatibility. Super G is generally backwards compatible with 802.11g.
80211n improves upon 802.11g significantly with an increase in the data rate to 600 Mbps. Channels operate at 40 MHz doubling the channel width from 20 MHz. 802.11n operates on both the 2.4 GHz and the 5 GHz bands. 802.11n also added multiple-input multiple-output antennas (MIMO).
Multiple-Input/Multiple-Output (MIMO) is a part of the new IEEE 802.11n wireless standard. It’s a technique that uses multiple signals to increase the speed, reliability, and coverage of wireless networks. It transmits multiple datastreams simultaneously, increasing wireless capacity to up to 100 or even 250 Mbps.
This wireless transmission method takes advantage of a radio transmission characteristic called multipath, which means that radio waves bouncing off surfaces such as walls and ceilings will arrive at the antenna at fractionally different times. This characteristic has long been considered to be a nuisance that impairs wireless transmission, but MIMO technology actually exploits it to enhance wireless performance.
MIMO sends a high-speed data stream across multiple antennas by breaking it into several lower-speed streams and sending them simultaneously. Each signal travels multiple routes for redundancy.
To pick up these multipath signals, MIMO uses multiple antennas and compares signals many times a second to select the best one. A MIMO receiver makes sense of these signals by using a mathematical algorithm to reconstruct the signals. Because it has multiple signals to choose from, MIMO achieves higher speeds at greater ranges than conventional wireless hardware does. collapse
Black Box Explains...Upgrading from VGA to DVI video.
Many new PCs no longer have traditional Cathode Ray Tube (CRT) computer monitors with a VGA interface. The latest high-end computers have Digital Flat Panels (DFPs) with a Digital Visual... more/see it nowInterface (DVI). Although most computers still have traditional monitors, the newer DFPs are coming on strong because flat-panel displays are not only slimmer and more attractive on the desktop, but they’re also capable of providing a much sharper, clearer image than a traditional CRT monitor.
The VGA interface was developed to support traditional CRT monitors. The DVI interface, on the other hand, is designed specifically for digital displays and supports the high resolution, the sharper image detail, and the brighter and truer colors achieved with DFPs.
Most flat-panel displays can be connected to a VGA interface, even though using this interface results in inferior video quality. VGA simply cant support the image quality offered by a high-end digital monitor. Sadly, because a VGA connection is possible, many computer users connect their DFPs to VGA and never experience the stunning clarity their flat-panel monitors can provide.
It’s important to remember that for your new DFP display to work at its best, it must be connected to a DVI video interface. You should upgrade the video card in your PC when you buy your new video monitor. Your KVM switches should also support DVI if you plan to use them with DFPs. collapse
Black Box Explains... Speaker wire gauge.
Wire gauge (often shown as AWG, for American Wire Gauge) is a measure of the thickness of the wire. The more a wire is drawn or sized, the smaller its... more/see it nowdiameter will be. The lower the wire gauge, the thicker the wire.
For example, a 24 AWG wire is thinner than a 14 AWG wire. A lower AWG means longer transmission distance and better integrity. As a rule of thumb, power loss decreases as the wire size increases.
When it comes to choosing speaker cable, consider a few factors: distance, the type of system and amplifier you have, the frequencies of the signals being handled, and any specifications that the speaker manufacturer recommends.
For most home applications where you simply need to run cable from your stereo to speakers in the same room—or even behind the walls to other rooms—16 AWG cable is usually fine.
If youre considering runs of more than 40 feet (12.1 m), consider using 14 AWG or even 12 AWG cable. They both offer better transmission and less resistance over longer distances. You should probably choose 12 AWG cable for high-end audio systems with higher power output or for low-frequency subwoofers. As a rule of thumb, power loss decreases as the wire size increases.
To terminate your cable, choose gold connectors. Because gold resists oxidation over time, gold connectors wear better and offer better peformance than other connectors do. collapse
DisplayPort is a digital video interface that was designed by the Video Electronics Standards Association (VESA) in 2006 and has been produced since 2008. It’s incredibly versatile, with the capability... more/see it nowto deliver digital video, audio, bidirectional communications, and accessory power over a single connector.
DisplayPort cables are targeted at the computer world rather than at consumer electronics. DisplayPort is used to connect digital audio/video computers, displays, monitors, projectors, HDTVs, splitters, extenders, and other devices that support resolutions up to 4K and beyond. Unlike HDMI, however, DisplayPort is an open standard with no royalties.
With the proper adapters, DisplayPort cable can carry DVI and HDMI signals, although this doesn’t work the other way around—DVI and HDMI cable can’t carry DisplayPort. Because DisplayPort can provide power to attached devices, DisplayPort to HDMI or DVI adapters don’t need a separate power supply.
DisplayPort supports cable lengths of up to 15 meters with maximum resolutions at cable lengths up to 3 meters. Bidirectional signaling enables DisplayPort to both send and receive data from an attached device.
DisplayPort v1.1: 10.8 Gbps over a 2-meter cable.
DisplayPort v1.2: 21.6 Gbps (4K). DisplayPort v1.2 also enables you to daisychain up to four monitors with only a single output cable. It also offers the future promise of DisplayPort Hubs that would operate much like a USB hub.
DisplayPort v1.3: 2.4 Gbps. (5K)
The standard DisplayPort connector is very compact and features latches that don’t add to the connector’s size. Unlike HDMI, a DisplayPort connector is easily lockable with a pinch-down locking hood, so it can't be easily dislodged. However, a quick squeeze of the connector releases the latch.
The Mini DisplayPort (MiniDP or mDP) is a miniatured version of the DisplayPort interface. It carries both digital and analog computer video and audio signals. Apple® introduced the Mini DisplayPort connector in 2008 and it is now on all new Mac® computers. It is also being used in newer PC notebooks. This small form factor connector fully supports the VESA DisplayPort protocol. It is particularly useful on systems where space is at a premium, such as laptops, or to support multiple connectors on reduced height add-in cards.
Black Box Explains…HDMI
The High-Definition Multimedia Interface (HDMI®) is the first digital interface to combine uncompressed high-definition video, up to eight channels of uncompressed digital audio, and intelligent format and command data in... more/see it nowa single cable. It is now the de facto standard for consumer electronics and high-definition video and is gaining ground in the PC world.
HDMI supports standard, enhanced, and high-definition video. It can carry video signals at resolutions beyond 1080p at 60 Hz (Full HD) up to 4K x 2K (4096 x 2160) as well as 3D TV.
HDMI also provides superior audio clarity. It supports multiple audio formats from standard stereo to multichannel surround sound.
HDMI offers an easy, standardized way to set up home theaters and AV equipment over one cable. Use it to connect audio/video equipment, such as DVD players, set-top boxes, and A/V receivers with an audio and/or video equipment, such as a digital TVs, PCs, cameras, and camcorders. It also supports multiple audio formats from standard stereo to multichannel surround sound. Plus it provides two-way communications between the video source and the digital TV, enabling simple remote, point-and-click configurations.
NOTE: HDMI also supports HDCP (High-bandwidth Digital Content Protection), which prevents the copying of digital audio and video content transmitted over HDMI able. If you have a device between the source and the display that supports HDMI but not HDCP, your transmission won't work, even over an HDMI cable.
HDMI offers significant benefits over older analog A/V connections. It's backward compatible with DVI equipment, such as PCs. TVs, and other electronic devices using the DVI standard. A DVI-to-HDMI adapter can be used without a loss of video quality. Because DVI only supports video signals, no audio, the DVI device simply ignores the extra audio data.
The HDMI standard was introduced in December 2002. Since then, there have been a number of versions with increasing bandwidth and/or transmission capabilities.
With the introduction of HDMI (June 2006), more than doubled the bandwidth from 4.95 Gbps to 10.2 Gbps (340 MHz). It offers support for 16-bit color, increased refresh rates, and added support for 1440p WQXGA. It also added support for xvYCC color space and Dolby True HD and DTS-HD Master Audio standards. Plus it added features to automatically correct audio video synchronization. Finally, it added a mini connector.
HDMI 1.3a (November 2006), HDMI 1.3b (March 2007, HDMI 1.3b1 (November 2007), and 1.3c (August 2008) added termination recommendations, control commands, and other specification for testing, etc.
HDMI 1.4 (May 2009) increased the maximum resolution to 4Kx 2K (3840 x 2160 p/24/25/30 Hz). It added an HDMI Ethernet channel for a 100-Mbps connection between two HDMI devices. Other advancements include: an Audio Return Channel, stereoscopic 3D over HDMI (HDMI 1.3 devices will only support this for 1080i), an automotive connection system, and the micro HDMI connector.
HDMI 1.4a (March 2010) adds two additional 3D formats for broadcast content.
HDMI 2.0 (August 2013), which is backwards compatible with earlier versions of the HDMI specification, significantly increases bandwidth up to 18 Gbps and adds key enhancements to support market requirements for enhancing the consumer video and audio experience.
HDMI 2.0 also includes the following advanced features:
Resolutions up to 4K@50/60 (2160p), which is four times the clarity of 1080p/60 video resolution, for the ultimate video experience.
Up to 32 audio channels for a multi-dimensional immersive audio experience.
Up to 1536Hz audio sample frequency for the highest audio fidelity.
Simultaneous delivery of dual video streams to multiple users on the same screen.
Simultaneous delivery of multi-stream audio to multiple users (up to four).
Support for the wide angle theatrical 21:9 video aspect ratio.
Dynamic synchronization of video and audio streams.
CEC extensions provide more expanded command and control of consumer electronics devices through a single control point.
Standard HDMI Cable: 1080i and 720p
Standard HDMI Cable with Ethernet
Automotive HDMI Cable
High Speed HDMI Cable: 1080p, 4K, 3D and Deep Color
High Speed HDMI Cable with Ethernet
There are four HDMI connector types.
Type A: 19 pins. It supports all SDTV, EDTV, and HDTV modes. It is electrically compatible with single-link DVI-D. HDMI 1.0 specification.
Type B: 29 pins. Offers double the video bandwidth of Type A. Use for very high-resolution displays such as WQUXGA. It's electronically compatible with dual-link DVI-D. HDMI 1.0 specification.
Type C Mini: 19 pins. This mini connector is intended for portable devices. It is smaller than Type A but has the same pin configuration and can be connected to Type A cable via an adapter or adapter cable. Type C is defined in HDMI 1.3.
Type D Micro: 19 pins. This also has the 19-pin configuration of Type A but is about the size of a micro-USB connector. Type D is defined in HDMI 1.4.
Recently, HDMI Licensing, LLC announced that all able would be tested as either Standard or High-Speed cables. Referring to cables based on HDMI standard (e.g. 1.2, 1.3 etc.) is no longer allowed.
Standard HDMI cable is designed for use with digital broadcast TV, cable TV, satellites TV, Blu-ray, and upscale DVD payers to reliably transmit up to 1080i or 720p video (or the equivalent of 75 MHz or up to 2.25 Gbps).
High-Speed HDMI reliably transmits video resolutions of 1080p and beyond, including advanced display technologies such as 4K, 3D, and Deep Color. High-Speed HDMI is the recommended cable for 1080p video. It will perform at speeds of 600 MHz or up to 18 Gbps, the highest bandwidth urgently available over an HDMI cable.
HDCP copy protection
HDMI also supports High-bandwidth Digital Content Protection (HDCP), which prevents the copying of content transmitted over HDMI cable. If you have a device between the source and the display that supports HDMI but not HDCP, your transmission won’t work, even over an HDMI cable.
Additional resources and licensing information is available at HDMI.org.
Fiber optic cable construction and types.
Multimode vs. single-mode
Multimode cable has a large-diameter core and multiple pathways of light. It is most commonly available in two core sizes: 50-micron and 62.5-micron.
Multimode fiber optic cable can... more/see it nowbe used for most general data and voice fiber applications such as adding segments to an existing network, and in smaller applications such as alarm systems and bringing fiber to the desktop. Both multimode cable cores use either LED or laser light sources.
Multimode 50-micron cable is recommended for premise applications?(backbone, horizontal, and intrabuilding connections). It should be considered for any new construction and for installations because it provides longer link lengths and/or higher speeds, particularly in the 850-nm wavelength, than 62.5-micron cable does.
Multimode cable commonly has an orange or aqua jacket; single-mode has yellow. Other colors are available for various applications and for identification purposes.
Single-mode cable has a small (8–10-micron) glass core and only one pathway of light. With only a single wavelength of light passing through its core, single-mode cable realigns the light toward the center of the core instead of simply bouncing it off the edge of the core as multimode does.
Single-mode cable provides 50 times more distance than multimode cable does. Consequently, single-mode cable is typically used in high-bandwidth applications and in long-haul network connections spread out over extended areas, including cable television and campus backbone applications. Telcos use it for connections between switching offices. Single-mode cable also provides higher bandwidth, so you can use a pair of single-mode fiber strands full-duplex at more than twice the throughput of multimode fiber.
Fiber optic cable consists of a core, cladding, coating, buffer strengthening fibers, and cable jacket.
The core is the physical medium that transports optical data signals from an attached light source to a receiving device. It is a single continuous strand of glass or plastic that’s measured (in microns) by the size of its outer diameter.
All fiber optic cable is sized according to its core’s outer diameter. The two multimode sizes most commonly available are 50 and 62.5 microns. Single-mode cores are generally less than 9 microns.
The cladding is a thin layer that surrounds the fiber core and serves as a boundary that contains the light waves and causes the refraction, enabling data to travel throughout the length of the fiber segment.
The coating is a layer of plastic that surrounds the core and cladding to reinforce the fiber core, help absorb shocks, and provide extra protection against excessive cable bends. These coatings are measured in microns (µ); the coating is 250µ and the buffer is 900µ.
Strengthening fibers help protect the core against crushing forces and excessive tension during installation. This material is generally Kevlar® yarn strands within the cable jacket.
The cable jacket is the outer layer of any cable. Most fiber optic cables have an orange jacket, although some types can have black, yellow, aqua or other color jackets. Various colors can be used to designate different applications within a network.
Simplex vs. duplex patch cables
Multimode and single-mode patch cables can be simplex or duplex.
Simplex has one fiber, while duplex zipcord has two fibers joined with a thin web. Simplex (also known as single strand) and duplex zipcord cables are tight-buffered and jacketed, with Kevlar strength members.
Because simplex fiber optic cable consists of only one fiber link, you should use it for applications that only require one-way data transfer. For instance, an interstate trucking scale that sends the weight of the truck to a monitoring station or an oil line monitor that sends data about oil flow to a central location.
Use duplex multimode or single-mode fiber optic cable for applications that require simultaneous, bidirectional data transfer. Workstations, fiber switches and servers, Ethernet switches, backbone ports, and similar hardware require duplex cable.
PVC (riser) vs. plenum-rated
PVC cable (also called riser-rated cable even though not all PVC cable is riser-rated) features an outer polyvinyl chloride jacket that gives off toxic fumes when it burns. It can be used for horizontal and vertical runs, but only if the building features a contained ventilation system. Plenum can replace PVC, but PVC cannot be used in plenum spaces.
“Riser-rated” means that the jacket is fire-resistant. However, it can still give off noxious fumes when overheated. The cable carries an OFNR rating and is not for use in plenums.
Plenum-jacketed cables have FEP, such as Teflon®, which emits less toxic fumes when it burns. A plenum is a space within the building designed for the movement of environmental air. In most office buildings, the space above the ceiling is used for the HVAC air return. If cable goes through that space, it must be “plenum-rated.”
Distribution-style vs. breakout-style
Distribution-style cables have several tight-buffered fibers bundled under the same jacket with Kevlar or fiberglass rod reinforcement. These cables are small in size and are typically used within a building for short, dry conduit runs, in either riser or plenum applications. The fibers can be directly terminated, but because the fibers are not individually reinforced, these cables need to be terminated inside a patch panel, junction box, fiber enclosure, or cabinet.
Breakout-style cables are made of several simplex cables bundled together, making a strong design that is larger than distribution cables. Breakout cables are suitable for riser and plenum applications.
Loose-tube vs. tight-buffered
Both loose-tube and tight-buffered cables contain some type of strengthening member, such as aramid yarn, stainless steel wire strands, or even gel-filled sleeves. But each is designed for very different environments.
Loose-tube cable is specifically designed for harsh outdoor environments. It protects the fiber core, cladding, and coating by enclosing everything within semi-rigid protective sleeves or tubes. Many loose-tube cables also have a water-resistant gel that surrounds the fibers. This gel helps protect them from moisture, so the cables are great for harsh, high-humidity environments where water or condensation can be a problem. The gel-filled tubes can also expand and contract with temperature changes. Gel-filled loose-tube cable is not the best choice for indoor applications.
Tight-buffered cable, in contrast, is optimized for indoor applications. Because it’s sturdier than loose-tube cable, it’s best suited for moderate-length LAN/WAN connections, or long indoor runs. It’s easier to install as well, because there’s no messy gel to clean up and it doesn’t require a fan-out kit for splicing or termination.
Indoor/outdoor cable uses dry-block technology to seal ruptures against moisture seepage and gel-filled buffer tubes to halt moisture migration. Comprised of a ripcord, core binder, a flame-retardant layer, overcoat, aramid yarn, and an outer jacket, it is designed for aerial, duct, tray, and riser applications.
Interlocking armored cable
This fiber cable is jacketed in aluminum interlocking armor so it can be run just about anywhere in a building. Ideal for harsh environments, it is rugged and rodent resistant. No conduit is needed, so it’s a labor- and money-saving alternative to using innerducts for fiber cable runs.
Outside-plant cable is used in direct burials. It delivers optimum performance in extreme conditions and is terminated within 50 feet of a building entrance. It blocks water and is rodent-resistant.
Interlocking armored cable is lightweight and flexible but also extraordinarily strong. It is ideal for out-of-the-way premise links.
Laser-optimized 10-Gigabit cable
Laser-optimized multimode fiber cable assemblies differ from standard multimode cable assemblies because they have graded refractive index profile fiber optic cable in each assembly. This means that the refractive index of the core glass decreases toward the outer cladding, so the paths of light towards the outer edge of the fiber travel quicker than the other paths. This increase in speed equalizes the travel time for both short and long light paths, ensuring accurate information transmission and receipt over much greater distances, up to 300 meters at 10 Gbps.
Laser-optimized multimode fiber cable is ideal for premise networking applications that include long distances. It is usually aqua colored.