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Black Box Explains...Shielded vs. unshielded cable.

The environment determines whether cable should be shielded or unshielded.

Shielding is the sheath surrounding and protecting the cable wires from electromagnetic leakage and interference. Sources of this electromagnetic activity... more/see it now(EMI)—commonly referred to as noise—include elevator motors, fluorescent lights, generators, air conditioners, and photocopiers. To protect data in areas with high EMI, choose a shielded cable.

Foil is the most basic cable shield, but a copper-braid shield provides more protection. Shielding also protects cables from rodent damage. Use a foil-shielded cable in busy office or retail environments. For industrial environments, you might want to choose a copper-braid shield.

For quiet office environments, choose unshielded cable. collapse


Black Box Explains...4K

4K is a term to describe a maximum video resolution of 4096 x 2400 pixels. However, the most commonly used resolution is UHD (Ultra High Definition) at 3840 x 2160... more/see it nowpixels. This resolution basically allows for four full HD signals of 1920 x 1080 pixels to be displayed on a single screen. Unfortunately, the pure pixel count doesn't tell the complete the story. The following overview provides an examination of some key differences to provide users with a better understanding of potential requirements to help select suitable solutions.

Technical Details

  • Maximum resolution: 4096 x 2400, with 3840 x 2160 reflecting between 8.9 Megapixel and 9.8 Megapixel
  • Refresh rate: 24p/30p/60p

  • Typical Interfaces
    DVI-D
    The DVI specification allows 1920 x 1200 pixels to be transmitted in single-link format or 2560 x 1600 (2048 x 2048) pixels in dual link. Typically, the single link is supported by 23- or 24-inch displays, commonly called Full HD panels. The dual-link resolutions require larger screen sizes of typically 27 inches (2560 x 1440), 30 inch (2560 x 1600), or square ATC displays of 2048 x 2048 pixels.

    Full 4K resolutions of 3840 x 2160 or higher over DVI dual link are possible, but only at less than 30 Hz due to bandwidth limitations. The bandwidth required for professional AV and PC environments can come to 4.95 Gbps (165 Mhz) for single link or 9.9 Gbps (2x 165 Mhz) for dual-link DVI.

    HDMI
    HDMI and DVI share the same digital video signal format, but HDMI 1.2 allows for higher pixel clock frequencies, resulting in higher bandwidth or resolutions and deeper color.

    The specifications vary based on the different HDMI versions. Up to HDMI 1.2 the specs more or less reflect those of DVI video. HDMI 1.3 and 1.4 exceed the dual-link DVI specs although it only uses a single link. HDMI 1.3/1.4 bandwidth is 10.2 Gbps (single link 140 Mhz).

    Most HDMI 4K appliances and displays currently on the market are limited to 30 Hz. The recently released HDMI 2.0 standard increases bandwidth to 18 Gpbs (600 Mhz), effectively matching the bandwidth of DisplayPort for supporting 4K at up to 60 fps. The first HDMI 2.0 displays supporting this full specification are presently showing up on the market. HDMI is commonly used on almost all consumer and professional AV equipment.

    DisplayPort 1.2
    DisplayPort is a slightly different, micro packet-based, video standard supporting a maximum bandwidth of approximately 17 Gbits. This currently makes it the only suitable single-connect option for full UHD (3840 x 2160) at 60 fps.

    DisplayPort is mainly used on PC graphic adapter cards. Note: all current graphics cards with DisplayPort support the full DisplayPort 1.2a specification of 5.4 Gbps per lane and therefore only support 30 fps rather than 60 fps 4K resolutions.

    Thunderbolt
    Thunderbolt 1.0 is an Apple-only interface for multi-purpose use including video. Thunderbolt is compatible with DP 1.1 and capable of natively outputting DisplayPort signals. Thunderbolt 2.0 is needed to support 4K at 60Hz, and is compatible with DisplayPort 1.2.

    Different ways of delivering 4K
    Depending on the specifications of the equipment being used, a 4K signal may be delivered in the following ways:

    Full spec 60 fps
  • Display/projector with four single-link DVI interfaces and synchronized channels. Acts like a video wall in just a single large device.
  • Display/projector with two dual-link DVI interfaces and synchronized channels. Acts like a video wall in just a single large device.
  • Display/projector with either two dula-link DVI or HDMI 1.4 inputs. The term used to describe this method is Multiple Protocol Transport (MPT).
  • Display with either DisplayPort, Thunderbolt, or upcoming HDMI 2.0 full spec interfaces.

  • 4K @ 24/30 fps
  • Display/projector with either one dual-link DVI or HDMI 1.4 input. (MPT.)
  • Display with either DisplayPort, Thunderbolt or upcoming HDMI 2.0 full spec interfaces.
  • collapse


    Black Box Explains...RS-232.

    RS-232, also known as RS-232C and TIA/EIA-232-E, is a group of electrical, functional, and mechanical specifications for serial interfaces between computers, terminals, and peripherals. The RS-232 standard was developed by... more/see it nowthe Electrical Industries Association (EIA), and defines requirements for connecting data communications equipment (DCE)—modems, converters, etc.—and data terminal equipment (DTE)—computers, controllers, etc.) devices. RS-232 transmits data at speeds up to 115 Kbps and over distances up to 50 feet (15.2 m).

    The standard, which is functionally equivalent to ITU V.24/V.28, specifies the workings of the interface, circuitry, and connector pinning. Both sync and async binary data transmission fall under RS-232. Although RS-232 is sometimes still used to transmit data from PCs to peripheral devices, the most common uses today are for network console ports and for industrial devices.

    Even though RS-232 is a “standard,” you can’t necessarily expect seamless communication between two RS-232 devices. Why? Because different devices have different circuitry or pinning, and different wires may be designated to perform different functions.

    The typical RS-232 connector is DB25, but some PCs and other data communication devices have DB9 connectors and many newer devices have RJ-45 RS-232 ports. To connect 9-pin PC ports or RJ-45 to devices with 25-pin connectors, you will require a simple adapter cable. collapse


    Black Box Explains... RJ-48

    An RJ-48 plug is often mistaken for RJ-45. On the outside, the two look identical—both are housed in a miniature 8-position jack. The difference is in the pairing of the... more/see it nowwires.

    In RJ-48, two of the wires are for transmit, two are for receive, and two are for the drain. The last two wires are reserved for future use.

    There are three subsets within RJ-48: RJ-48C, RJ-48X, and RJ-48S.

    RJ-48C and RJ-48X are very similar. Both use lines 1, 2, 4, and 5 and connect T1 lines. The RJ-48C is more common. The difference is that RJ-48X connectors have shorting bars.

    RJ-48S uses lines 1, 2, 7, and 8. It connects 56K DDS lines. collapse


    Black Box Explains...UARTs at a glance.

    Universal Asynchronous Receiver/Transmitters (UARTs) are integrated circuits that convert bytes from the computer bus into serial bits for transmission. By providing surplus memory in a buffer, UARTs help applications overcome... more/see it nowthe factors that can hinder system performance, providing maximum throughput to high-performance peripherals without slowing down CPUs.

    Early UARTs such as 8250 and 16450 did not include buffering (RAM or memory). With the advent of higher-speed devices, the need for UARTs that could handle more data became critical. The first buffered UART was the 16550, which incorporates a 16-byte First In First Out (FIFO) buffer and provides greater throughput than its predecessors.

    Manufacturers have been developing enhanced UARTs that continue to increase performance standards. These faster chips provide improvements such as larger buffers and increased speeds. Here are the rates of today’s common UARTs:

    UART FIFO Buffer Rate Supported
    16550 16-byte 115.2 kbps
    16554 16-byte 115.2 kbps
    16650 32-byte 460.8 kbps (burst rate)
    16654 64-byte 460.8 kbps (burst rate)
    16750 64-byte 460.8 kbps (burst rate)
    16850 128-byte 460.8 kbps (sustained rate)
    16854 128-byte 460.8 kbps (sustained rate) collapse


    Black Box Explains...What to look for in a channel solution.


    Channel solution. You hear the term a lot these days to describe complete copper or fiber cabling systems. But what exactly is a channel solution and what are its benefits?... more/see it now

    A definition.
    A channel solution is a cabling system from the data center to the desktop where every cable, jack, and patch panel is designed to work together and give you consistent end-to-end performance when compared with the EIA/TIA requirements.

    Its benefits.
    A channel solution is beneficial because you have some assurance that your cabling components will perform as specified. Without that assurance, one part may not be doing its job, so your entire system may not be performing up to standard, which is a problem — especially if you rely on bandwidth-heavy links for video and voice.

    What to look for.
    There are a lot of channel solutions advertised on the Internet and elsewhere. So what exactly should you be looking for?

    For one, make sure it’s a fully tested, guaranteed channel solution. The facts show an inferior cabling system can cause up to 70 percent of network downtime — even though it usually represents only 5 percent of an initial network investment. So don’t risk widespread failure by skimping on a system that doesn’t offer guaranteed channel performance. You need to make sure the products are engineered to meet or go beyond the key measurements for CAT5e or CAT6 performance.

    And, sure, they may be designed to work together, but does the supplier absolutely guarantee how well they perform as part of a channel — end to end? Don’t just rely on what the supplier says. They may claim their products meet CAT5e or CAT6 requirements, but the proof is in the performance. Start by asking if the channel solution is independently tested and certified by a reputable third party. There are a lot of suppliers out there who don’t have the trademarked ETL approval logo, for example.

    What ETL Verified means.
    The ETL logo certifies that a channel solution has been found to be in compliance with recognized standards. To ensure consistent top quality, Black Box participates in independent third-party testing by InterTek Testing Services/ETL Semko, Inc. Once a quarter, an Intertek inspector visits Black Box and randomly selects cable and cabling products for testing.

    The GigaTrue® CAT6 and GigaBase® CAT5e Solid Bulk Cable are ETL Verified at the component level to verify that they conform to the applicable industry standards. The GigaTrue® CAT6 and GigaBase® CAT5e Channels, consisting of bulk cable, patch cable, jacks, patch panels, and wiring blocks, are tested and verified according to industry standards in a LAN environment under InterTek’s Cabling System Channel Verification Program. For the latest test results, contact our FREE Tech Support. collapse


    Black Box Explains…CAT6A UTP vs. F/UTP.

    CAT6A is currently the cable of choice for future-proofing cabling installations and for 10-GbE networks.

    There are two types of CAT6A cable, unshielded (UTP) and shielded (F/UTP). F/UTP denotes foiled/unshielded... more/see it nowtwisted pair and consists of four unshielded twisted pairs encased in an overall foil shield. This is not to be confused with an S/FTP (screened/foiled twisted pair) cable, which has four individually shielded twisted pairs encased in an overall braided shield.

    CAT6A UTP
    CAT6A UTP is constructed in a certain way to help eliminate crosstalk and ANEXT. (ANEXT is the measurement of the signal coupling between wire pairs in different and adjacent cables.) This includes larger conductors (23 AWG minimum), tighter twists, an extra internal airspace, an internal separator between the pairs, and a thicker outer jacket. These features also increase the outer diameter of the cable, typically to .35 inches in diameter, up from .25 inches for CAT6 cable. This increased diameter creates a greater distance between pairs in adjacent links, thus reducing the between-channel signal coupling. But CAT6A UTP cable is still affected by ANEXT.

    According to the standards, ANEXT can be improved by laying CAT6A UTP cable loosely in pathways and raceways with space between the cables. This contrasts to the tightly bundled runs of CAT6/5e cable we are used to. The tight bundles present a worst-case scenario of six cables around one, thus the center cable would be adversely affected by ANEXT. Testing for ANEXT is a complex and time-consuming process where all possible wire-pair combinations are checked. It can take up to 50 minutes to test one link in a bundle of 24 CAT6A UTP cables.

    CAT6A F/UTP
    CAT6A F/UTP denotes foiled/unshielded twisted pairs and consists of four unshielded twisted pairs encased in an overall foil shield. ANEXT, and the time needed to test for it, can be greatly reduced, if not eliminated completely, by using CAT6A F/UTP. The foil shield acts as a barrier preventing external EMI/RFI from coupling onto the twisted pairs. It also prevents data signals from leaking out of the cable, making the cable more difficult to tap and better for secure installations. Studies also have shown that CAT6A F/UTP cable provides significantly more headroom (as much as 20 dB) than CAT6A UTP in 10-GbE over copper systems.

    Bigger isn't always better.
    CAT6A UTP cable has an overall allowable diameter of 0.354 inches. CAT6A F/UTP cable has an average outside diameter of 0.265–0.30 inches. That’s smaller than the smallest CAT6A UTP cable. An increase in the outside diameter (O.D.) of 0.1 inch, from 0.25 inches to 0.35 inches for example, represents a 21% increase in fill volume. In general, CAT6A F/UTP cable provides a minimum of 35% more fill capacity that CAT6A UTP cable.

    Also because of its large diameter, CAT6A UTP requires a larger bend radius, more pathways, less dense patch panel connections, and extensive ANEXT testing.

    CAT6A F/UTP cable is actually easier to handle, requires less bend radius, and uses smaller pathways. In addition, innovations in connector technology has made terminating CAT6A F/UTP cable simpler. In terms of grounding, the requirements for both UTP and F/UTP cable fall under TIA/EIA J-STD-607-A Commercial Building Grounding (Earthing) and Bonding Requirements for Telecommunications.

    The advantages of CAT6A F/UTP vs. UTP
    In summary, there are a number of advantages of using CAT6A F/UTP over CAT6A UTP in 10-GbE networks.

    1. Shielding eliminates ANEXT and EMI/RFI problems and testing.
    2. Data line security is enhanced because of shielding.
    3. Lighter, slimmer cable provides higher port density.
    4. Smaller outside diameter cable is easier to handle and reduces installation costs.
    5. Shielded cable uses less space in conduits.

    For more information, see the CAT6A F/UTP vs. UTP: What You Need to Know white paper in the Resources section at blackbox.com. collapse


    Black Box Explains...Augmented Category 6 (CAT6A).


    Augmented Category 6 (CAT6a)–Class Ea was ratified in February 2008. This standard calls for 10-Gigabit Ethernet data transmission over a 4-pair copper cabling system up to 100 meters. CAT6a extends... more/see it nowCAT6 electrical specifications from 250 MHz to 500 MHz. It introduces the ANEXT requirement. It also replaces the term Equal Level Far-End Crosstalk (ELFEXT) with Attenuation to Crosstalk Ratio, Far-End (ACRF) to mesh with ISO terminology. CAT6a provides improved insertion loss over CAT6. It is a good choice for noisy environments with lots of EMI. CAT6a is also well-suited for use with PoE+.

    CAT6a UTP cable is significantly larger than CAT6 cable. It features larger conductors, usually 22 AWG, and is designed with more space between the pairs to minimize ANEXT. The outside diameter of CAT6a cable averages 0.29–0.35" compared to 0.21–0.24" for CAT6 cable. This reduces number of cables you can fit in a conduit. At a 40% fill ratio, you can run three CAT6a cables in a 3/4" conduit vs. five CAT6 cables.

    There are two types of CAT6a cable, UTP and F/UTP.

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    Black Box Explains...Choosing SCSI cables.

    1. Quality. Your system’s performance depends on the quality of your SCSI cables. Without high-quality cables specifically designed for SCSI applications, you could be jeopardizing your SCSI lifeline. Inferior cables,... more/see it nowadapters, and terminators can cause random errors, data corruption, or even a system crash! Black Box® SCSI Cables and components are the absolute best-quality products. And they’re guaranteed for life.

    2. Length. For peak network performance, make sure your cables are the right length. As cable runs get longer, signals weaken and are more susceptible to noise. Always use the shortest cable for the task. And stay within the SCSI-1 and SCSI-2 standards of six meters or three meters for Fast SCSI. Remember, this is the total length of the bus, including all internal and external cables. collapse


    Black Box Explains... Matrix video switches.

    Matrix switches enable computers to mix and match the output of multiple PCs on multiple video monitors.

    For instance, if your operation has four PCs and you want to display the... more/see it nowvideo on one monitor to the other three monitors, a matrix video switch is what you need to handle the job. Use matrix switches for:
    • Trade shows—Set up a wall of video to wow the senses of attendees.
    • Transportation schedules—Provide real-time updates of flights or deliveries on multiple screens.
    • Training demonstrations—Control each screen’s video to focus everyone’s attention on what’s important. collapse

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