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Black Box Explains...Breakout-style cables.

With breakout- or fanout-style cables, the fibers are packaged individually. A breakout cable is basically several simplex cables bundled together in one jacket. Breakout cables are suitable for riser and... more/see it nowplenum applications, and conduit runs.

This differs from distribution-style cables where several tight-buffered fibers are bundled under the same jacket.

This design of the breakout cable adds strength to the cable, although that makes it larger and more expensive than distribution-style cables.

Because each fiber is individually reinforced, you can divide the cable into individual fiber lines. This enables quick connector termination, and eliminates the need for patch panels.

Breakout cable can also be more economical because it requires much less labor to terminate.

You may want to choose a cable that has more fibers than you actually need in case of breakage during termination or for future expansion. collapse


Black Box Explains...Category 6.

Category 6 (CAT6)–Class E has a specified frequency of 250 MHz, significantly improved bandwidth capacity over CAT5e, and easily handles Gigabit Ethernet transmissions. In recent years, it has been the... more/see it nowcable of choice for new structured cabling systems. CAT6 supports 1000BASE-T and, depending on the installation, 10GBASE-T (10-GbE).

10-GbE over CAT6 introduces the problem of Alien Crosstalk (ANEXT), the unwanted coupling of signals between adjacent pairs and cables. Because ANEXT in CAT6 10-GbE networks is so dependent on installation practices, TSB-155 qualifies 10-GbE over CAT6 up to 55 meters and requires it to be 100% tested. To mitigate ANEXT in CAT6, it is recommended that you unbundle the cables and increase the separation between the cables.

You can always contact Black Box Tech Support to answer your cabling questions. Our techs can recommend cable testers and steer you in the right direction when you’re installing new cabling. And the advice is FREE! collapse


Black Box Explains…Digital Visual Interface (DVI) connectors.

The DVI (Digital Video Interface) technology is the standard digital transfer medium for computers while the HDMI interface is more commonly found on HDTVs, and other high-end displays.

The Digital... more/see it nowVisual Interface (DVI) standard is based on transition-minimized differential signaling (TMDS). There are two DVI formats: Single-Link and Dual-Link. Single-link cables use one TMDS-165 MHz transmitter and dual-link cables use two. The dual-link cables double the power of the transmission. A single-link cable can transmit a resolution ?of 1920 x 1200 vs. 2560 x 1600 for a dual-link cable.

There are several types of connectors: ?DVI-D, DVI-I, DVI-A, DFP, and EVC.

  • DVI-D is a digital-only connector for use between a digital video source and monitors. DVI-D eliminates analog conversion and improves the display. It can be used when one or both connections are DVI-D.
  • DVI-I (integrated) supports both digital and analog RGB connections. It can transmit either a digital-to-digital signals or an analog-to-analog signal. It is used by some manufacturers on products instead of separate analog and digital connectors. If both connectors are DVI-I, you can use any DVI cable, but a DVI-I is recommended.
  • DVI-A (analog) is used to carry an DVI signal from a computer to an analog VGA device, such as a display. If one or both of your connections are DVI-A, use this cable. ?If one connection is DVI and the other is ?VGA HD15, you need a cable or adapter ?with both connectors.
  • DFP (Digital Flat Panel) was an early digital-only connector used on some displays.
  • EVC (also known as P&D, for ?Plug & Display), another older connector, handles digital and analog connections.
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    S/PDIF

    S/PDIF (Sony/Philips Digital Interface Format) is a type of digital audio transfer file format developed primarily by Sony and Philips. It enables the transfer of digital audio without converting it... more/see it nowto and from analog, which can degrade the signal.

    S/PDIF is typically used to connect consumer audio equipment over short distances. The connector is found on equipment such as a DAT (Digital Audio Tape) device, home theater amplifiers, etc. S/PDIF is based on the professional AES3 interconnect standard.

    S/PDIF signals are carried over two types of cables. The first is a 75-ohm coaxial cable with orange RCA connectors. The second is a fiber cable with TOSLINK connectors. collapse


    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.

    Construction
    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
    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.

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    Black Box Explains...10GBASE-T standard.

    In June 2006, the IEEE approved the standard for 10 Gigabit/sec Ethernet, or 10GBASE-T (10-GbE). 10-GbE transmission requires a bandwidth of 500 MHz.

    The 10-GbE standards.
    The cabling industry is developing... more/see it nowtwo different standards that can be used in 10-GbE applications. One is for use with Category 6 (CAT6) cable, and one is for Augmented Category 6 (CAT6a).

    Alien Crosstalk.
    Before discussing the standards, a definition of Alien Crosstalk is needed.

    Alien Crosstalk (ANEXT) is a critical measurement unique to 10-GbE systems. Crosstalk, measured in 10/100/1000BASE-T systems, is the mixing of signals between wire pairs within a cable. Alien Crosstalk is the measurement of the signal coupling between wire pairs in different, adjacent cables.

    The amount of ANEXT depends on a number of factors, including the promixity of adjacent cables and connectors, the cable length, cable twist density, and EMI. Patch panels and connecting hardware are also affected by ANEXT.

    With ANEXT, the affected cable is called the disturbed or victim cable. The surrounding cables are the disturbers.

    10-GbE using CAT6.
    The first set of standards defines cabling performance when using Category 6/Class E cabling for 10-GbE applications. The TIA/EIA version will be the Technical Systems Bulletin 155 (TSB 155). ISO/IEC TR 24750 is a technical report to be used for measuring existing Class E systems.

    No matter what the cable length is, CAT6 cable must meet 10-GbE electrical and ANEXT specifications up to 500 MHz. However, the CAT6 standard now specifies measurements only to 250 MHz, and it does not have an ANEXT requirement. There is no guarantee CAT6 can support a 10-GbE system. But the TSB provides guidelines for ways to help mitigate ANEXT. One way to lessen or eliminate ANEXT is to use shielded equipment and cables. Another way is to follow installation guidelines, such as using non-adjacent patch panels, separating equipment cords, unbundling horizontal cabling, etc.

    10GbE using CAT6a.
    The second set of standards will define Augmented Category 6 (CAT6a) and Augmented Class E (Class Ea) cabling. The newer, augmented cabling systems are designed to support 10-GbE over a 100-meter horizontal channel.

    The TIA/EIA version is in draft and will be published as ANSI/TIA/EIA-568B.2-AD10. It recognizes both UTP and STP CAT6a systems. It also extends CAT6 electrical parameters such as NEXT, FEXT, return loss, insertion loss, and more to 500 MHz. It specifies near- and far-end Alien Crosstalk (ANEXT, AFEXT) to 500 MHz. It also goes beyond IEEE 802.3an by establishing the electrical requirements for the permanent link and cabling components. The ISO Class Ea standard will be published in a new edition of the 11801 standard.

    These standards specify requirements for each component in the channel, such as cable and connecting hardware, as well as for the permanent link and the channel. collapse


    Black Box Explains...SCSI Ultra2 and LVD (Low-Voltage Differential).

    Small Computer Systems Interface (SCSI), pronounced “scuzzy,” has been the dominant technology used to connect computers and high-speed peripherals since the 1980s. SCSI technology is constantly evolving to accommodate increased... more/see it nowbandwidth needs. One of the more recent developments is Ultra2 SCSI.

    Because Ultra2 SCSI is backward compatible, it works with all legacy equipment. Ultra2 doubles the possible bandwidth on the bus from 40 to 80 MBps! Just as importantly, Ultra2 supports distances up to 12 meters (39.3 ft.) for a multiple-device configuration. Ultra2 uses Low-voltage Differential (LVD) techniques to transfer data at faster rates with fewer errors. Don’t confuse Ultra2 with LVD. Ultra2 is a data-transfer method; LVD is the signaling technique used to transfer the data.

    Cables are very important when designing or upgrading a system to take advantage of Ultra2 SCSI. Cables and connectors must be of high quality and they should come from a reputable manufacturer to prevent crosstalk and minimize signal radiation. BLACK BOX® Ultra2 LVD cables are constructed of the finest-quality components to provide your system with the maximum protection and highest possible data-transfer rates. collapse


    Black Box Explains... Pulling eyes and fiber cable.

    Fiber optic cable can be damaged if pulled improperly. Broken or cracked fiber, for example, can result from pulling on the fiber core or jacket instead of the strength member.... more/see it nowAnd too much tension or stress on the jacket, as well as too tight of a bend radius, can damage the fiber core. If the cable’s core is harmed, the damage can be difficult to detect.

    Once the cable is pulled successfully, damage can still occur during the termination phase. Field termination can be difficult and is often done incorrectly, resulting in poor transmission. One way to eliminate field termination is to pull preterminated cable. But this can damage the cable as well because the connectors can be knocked off during the pulling process. The terminated cable may also be too bulky to fit through ducts easily. To help solve all these problems, use preterminated fiber optic cable with a pulling eye. This works best for runs up to 2000 feet (609.6 m).

    The pulling eye contains a connector and a flexible, multiweave mesh-fabric gripping tube. The latched connector is attached internally to the Kevlar®, which absorbs most of the pulling tension. Additionally, the pulling eye’s mesh grips the jacket over a wide surface area, distributing any remaining pulling tension and renders it harmless. The end of the gripping tube features one of three different types of pulling eyes: swivel, flexible, or breakaway.

    Swivel eyes enable the cable to go around bends without getting tangled. They also prevent twists in the pull from being transferred to the cable. A flexible eye follows the line of the pull around corners and bends, but it’s less rigid. A breakaway eye offers a swivel function but breaks if the tension is too great. We recommend using the swivel-type pulling eye.

    A pulling eye enables all the fibers to be preterminated to ensure better performance. The terminated fibers are staggered inside the gripping tube to minimize the diameter of the cable. This enables the cable to be pulled through the conduit more easily. collapse


    Black Box Explains...Gold plating.

    Get premium-quality connectors from Black Box. The 24-karat gold plating ensures better signal transmission and no corrosion. The shielding and heavy gold conductors provide improved performance.


    Black Box Explains...Insertion loss.

    Insertion loss is a power loss that results from inserting a component into a previously continuous path or creating a splice in it. It is measured by the amount of... more/see it nowpower received before and after the insertion.

    In copper cable, insertion loss measures electrical power lost from the beginning of the run to the end.

    In fiber cable, insertion loss (also called optical loss) measures the amount of light lost from beginning to end. Light can be lost many ways: absorption, diffusion, scattering, dispersion, and more. It can also be from poor connections and splices in which the fibers don’t align properly.

    Light loss is measured in decibels (dBs), which indicate relative power. A loss of 10 dB means a tenfold reduction in power.

    Light strength can be measured with optical power meters, optical loss test sets, and other test sets that send a known light source through the fiber and measure its strength on the other end. collapse

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