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.
Black Box Explains... Plasma vs. LCD Screens
When deciding whether to use plasma or liquid crystal diode (LCD) displays for your applications, you need to consider many factors. Both provide brilliant color, sharp text contrast, and crystal-clear... more/see it nowimages. But the way in which plasma and LCD screens process and display incoming video/computer signals is markedly different.
Compare and contrast.
Both plasma and LCD technology provide stark enough contrasts to make displays sharp and pleasing. But when it comes to contrast output, plasma technology outperforms LCD screens. Some plasma displays have a 3000:1 contrast ratio, which is the measure of the blackest black compared to the whitest white. LCDs use electric charges to untwist liquid crystals, thereby blocking light and emitting darker pixels. Despite this process, LCD displays dont produce more than a 1000:1 contrast ratio.
Clarity thats light waves ahead.
Pixels contain enough information to produce every color in the spectrum. Because plasmas use each and every pixel on their screens, color information is reproduced more accurately. Plasma screens display moving images with remarkable clarity, though burn-in can be an issue. For displays with lots of light and dark imagery, plasma panels provide excellent performance with their high-contrast levels, color saturation, and overall brightness.
LCD displays, on the other hand, manipulate light waves and reproduce colors by subtracting colors from white light. Though this makes it more difficult to maintain color accuracy and vibrancy compared to plasma screens, LCDs have an advantage with their higher-than-average number of pixels per square inch. These additional pixels make LCD technology better at displaying static images from computers or VGA sources in full-color detail. Plus, theres no flicker and very little screen burn-in.
Applications with large amounts of data—such as those found on spreadsheets—display particularly well on LCD monitors.
Brilliant displays that go on and on.
With LCD screens, there are essentially no parts to wear out. LCD screens last as long as their backlights do, with displays lasting, on average, 50,000–75,000 hours. Thats why LCD screens are especially good for long-term applications, such as digital signage or displays that require around-the-clock use.
Plasma screens, however, use a combination of electric currents and noble gases (argon, neon, and xenon) to produce a glow, which in turn yields brilliant color. The half-life of these gases, however, is only around 25,000 hours. The glow they produce grows dimmer over time.
The right angle can make all the difference.
Plasmas light every pixel on the screen, making the brightness on the screen consistent and giving plasmas the edge when it comes to viewing angles. In fact, plasma screens have as much as a 160° viewing angle compared to LCDs. This makes viewing the images on the screen easier to see from a variety of angles. In doing so, however, plasmas consume much more power.
LCDs display at 130–140° angles, but their use of fluorescent backlighting requires much less power to operate than plasmas. This also makes LCDs less prone to burn-in or ghosting of images.
Black Box Explains...Category wiring standards
The ABCs of standards
There are two primary organizations dedicated to developing and setting structured cabling standards. In North America, standards are issued by the Telecommunications Industry Association (TIA),... more/see it nowwhich is accredited by the American National Standards Institute (ANSI). The TIA was formed in April 1988 after a merger with the Electronics Industry Association (EIA). That’s why its standards are commonly known as ANSI/TIA/EIA, TIA/EIA, or TIA.
Globally, the organizations that issue standards are the International Electrotechnical Commission (IEC) and the International Organization for Standardization (ISO). Standards are often listed as ISO/IEC. Other organizations include the Canadian Standards Association (CSA), CENELEC (European Committee for Electrotechnical Standardizations), and the Japanese Standards Association (JSA/JSI).
The committees of all these organizations work together and the performance requirements of the standards are very similar. But there is some confusion in terminology.
The TIA cabling components (cables, connecting hardware, and patch cords) are labeled with a ”category.” These components together form a permanent link or channel that is also called a ”category.” The ISO/IEC defines the link and channel requirements with a ”class” designation. But the components are called a ”category.”
Category 5 (CAT5) —ratified in 1991. It is no longer recognized for use in networking.
Category 5e (CAT5e), ISO/IEC 11801 Class D, ratified in 1999, is designed to support full-duplex, 4-pair transmission in 100-MHz applications. The CAT5e standard introduced the measurement for PS-NEXT, EL-FEXT, and PS-ELFEXT. CAT5e is no longer recognized for new installations. It is commonly used for 1-GbE installations.
Category 6 (CAT6) – Class E has a specified frequency of 250 MHz, significantly improved bandwidth capacity over CAT5e, and easily handles Gigabit Ethernet transmissions. CAT6 supports 1000BASE-T and, depending on the installation, 10GBASE-T (10-GbE).
10-GbE over CAT6 introduces 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, TIA TSB-155-A and ISO/IEC 24750 qualifies 10-GbE over CAT6 over channels of 121 to 180 feet (37 to 55 meters) and requires it to be 100% tested, which is extremely time consuming. To mitigate ANEXT in CAT6, it is recommended that the cables be unbundled, that the space between cables be increased, and that non-adjacent patch panel ports be used. If CAT6 F/UTP cable is used, mitigation is not necessary and the length limits do not apply. CAT6 is not recommended for new 10-GbE installations.
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 CAT6 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 the 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.
CAT6A UTP vs. F/UTP. Although shielded cable has the reputation of being bigger, bulkier, and more difficult to handle and install than unshielded cable, this is not the case with CAT6A F/UTP cable. It is actually easier to handle, requires less space to maintain proper bend radius, and uses smaller conduits, cable trays, and pathways. CAT6A UTP has a larger outside diameter than CAT6A F/UTP cable. This creates a great difference in the fill rate of cabling pathways. An increase in the outside diameter of 0.1", from 0.25" to 0.35" for example, represents a 21% increase in fill volume. In general, CAT6A F/UTP provides a minimum of 35% more fill capacity than CAT6A UTP. In addition, innovations in connector technology have made terminating CAT6A F/UTP actually easier than terminating bulkier CAT6A UTP.
Category 7 (CAT7) –Class F was published in 2002 by the ISO/IEC. It is not a TIA recognized standard and TIA plans to skip over it.
Category 7 specifies minimum performance standards for fully shielded cable (individually shielded pairs surrounded by an overall shield) transmitting data at rates up to 600 MHz. It comes with one of two connector styles: the standard RJ plug and a non-RJ-style plug and socket interface specified in IEC 61076-2-104:2.
Category 7a (CAT7a) –Class Fa (Amendment 1 and 2 to ISO/IEC 11801, 2nd Ed.) is a fully shielded cable that extends frequency from 600 MHz to 1000 MHz.
Category 8 – The TIA decided to skip Category 7 and 7A and go to Category 8. The TR-42.7 subcommittee is establishing specs for a 40-Gbps twisted-pair solution with a 2-GHz frequency. The proposed standard is for use in a two-point channel in a data center at 30 meters. It is expected to be ratified in February 2016. The TR-42.7 subcommittee is also incorporating ISO/IEC Class II cabling performance criteria into the standard. It is expected to be called TIA-568-C.2-1. The difference between Class I and Class II is that Class II allows for three different styles of connectors that are not compatible with one another or with the RJ-45 connector. Class I uses an RJ-45 connector and is backward compatible with components up to Category 6A.
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...KVMoIP access technology.
KVMoIP access technology extends keyboard, video, and mouse (KVM) signals from any computer or server over TCP/IP via a LAN, WAN, or Internet connection. Through this KVM over IP (KVMoIP)... more/see it nowconnection, remote users can access and control a number of servers simultaneously from wherever they are, inside or outside the organization, and anywhere in the world. This technology works in diverse hardware environments and is ideal for managing multilocation data centers and branch offices.
These capabilities translate into real savings for companies having to deal with the proliferation of servers in many offices, particularly for corporations and government agencies required to deliver 24/7 uptime and real-time access to mission-critical servers 365 days a year.
KVMoIP products combine the advantages of remote access software with the benefits of KVM switching technology. Like most KVM switches, KVMoIP products don’t require any software to be loaded on the host computers. They interface directly with the keyboard, monitor, and mouse connectors of the host computer or KVM switch. Circuitry within the KVMoIP device digitizes the incoming video signal and processes it into digital data that is communicated to a viewer program running on a remote client computer over a LAN/WAN or the public Internet.
By addressing network issues from a remote location, you can simply manage issues from your desk, or even save yourself the hassle of traveling to a site in the middle of the night. Use a browser-based connection, even a cell phone or PDA, to reboot or administer a roomful of servers remotely—a real convenience.
KVMoIP products that feature virtual media technology take that convenience further. They enable a remote user to effortlessly move files from a mass storage device—a USB flash drive or CD-ROM drive, for instance—from your location to the computer on which you’re working. Cost savings are realized through reduced downtime and less travel. Plus, in some cases, there‘s no to need replace existing KVM switches with proprietary ones to get a KVMoIP server-control solution.
The Black Box difference
Black Box® ServSwitch™ KVMoIP solutions go further than many other KVMoIP products on the market. They not only enable you to access remote servers, but they do this at the BIOS level—important when you go need to troubleshoot from off-site and don’t want to a dispatch
a technician. Install or recover software applications and install OS patches from your location anywhere in the world. Plus, this BIOS-level control is possible regardless of the server’s brand or model and even works if the operating system is down.
The ServReach™ system is also designed for IT managers seeking global centralized KVM management in a world of mushrooming servers and complexity. This global platform works by consolidating all server access and devices via locally connected KVMoIP devices. All this hardware is then united under a single management appliance or software “umbrella” providing global, yet fully secure, out-of-band control.
The ServReach system works seamlessly with more than 500 variations of analog KVM switches from a multitude of vendors and manufacturers. Because it’s vendor independent, you don’t need to replace your data center’s entire KVM infrastructure. ServReach simply
grafts global centralized KVM management onto the existing server room/data center, aligning with third-party KVM switches already in place. This is done with the ServReach KVMGate (KVIP1000A), an IP gateway device designed to connect to each of the legacy KVM devices to provide global centralized KVM management for a fraction of the cost of competitive systems, ensuring a faster and greater ROI.
If you’re planning on opening or acquiring a new data center or a large number of new servers, the ServReach KVManager (KVMGR) is the answer. It can provide any-by-any access via the ServReach KVMCube (KVIP1001A), a compact, rackmountable, digital matrix IP device that gives fully secure, non-blocking access for any of the users to any of the servers simultaneously.
In addition, the servers controlled by legacy KVM switches via KVMGate can still be managed by the ServReach KVManager at
the same time as the new servers controlled through a gateway. With all the servers under the same KVManager umbrella, data centers can now easily acquire new servers and devices without having to worry about how to incorporate the new infrastructure with the old.
For more information on Black Box KVMoIP solutions, visit blackbox.com/go/ServReach. Find out more by watching a KVMoIP demo and accessing related white papers. collapse
Black Box Explains...USB 2.0 and USB OTG.
The Universal Serial Bus (USB) hardware (plug-and-play) standard makes connecting peripherals to your computer easy.
USB 1.1, introduced in 1995, is the original USB standard. It has two data rates:... more/see it now12 Mbps for devices such as disk drives that need high-speed throughput and 1.5 Mbps for devices such as joysticks that need much lower bandwidth.
In 2002, a newer specification, USB 2.0, or Hi-Speed USB 2.0, gained wide acceptance in the industry. This version is both forward- and backward-compatible with USB 1.1. It increases the speed of the peripheral to PC connection from 12 Mbps to 480 Mbps, or 40 times faster than USB 1.1!
This increase in bandwidth enhances the use of external peripherals that require high throughput, such as CD/DVD burners, scanners, digital cameras, video equipment, and more. USB 2.0 supports demanding applications, such as Web publishing, in which multiple high-speed devices run simultaneously. USB 2.0 also supports Windows® XP through a Windows update.
An even newer USB standard, USB On-The-Go (OTG), is also in development. USB OTG enables devices other than a PC to act as a host. It enables portable equipment—such as PDAs, cell phones, digital cameras, and digital music players—to connect to each other without the need for a PC host.
USB 2.0 specifies three types of connectors: the A connector, the B connector, and the Mini B connector. A fourth type of connector, the Mini A (used for smaller peripherals such as mobile phones), was developed as part of the USB OTG specification. collapse
Black Box Explains...Digital Visual Interface (DVI) cables.
The Digital Visual Interface (DVI) standard is 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... more/see it nowlow level to create transitions that convey data. To minimize the number of transitions needed to transfer data, TMDS uses a pair of signal wires. 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.
There are different types of DVI connectors: DVI-D, DVI-I, DVI-A, DFP, and EVC. DVI-D is a digital-only connector.
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. collapse
Black Box Explains...Stream mode vs. burst mode/prompt mode.
Computers and mice must communicate with each other in order to operate properly. Most computers and mice communicate via a method called “stream mode”—as a mouse is being moved, it... more/see it nowsends the coordinates of its new position in a constant stream of information.
However, some computers communicate via a method known as “burst” or “prompt” mode. With this method, the mouse holds its data until the CPU sends a request (or “prompt”) for it. This mode of communication presents a problem for many KVM switches, as they normally pass along mouse coordinates in a stream mode. This results in a CPU receiving data when it isn’t expecting it, and the mouse simply won’t function properly.
All ServSwitch™ products contain support for stream-mode CPUs, and several ServSwitch products support both stream and burst/prompt modes. Call our FREE Tech Support about requirements for your application. collapse
Black Box Explains...The 13W3 connector.
The 13W3 connector, also called a 13C3 or DB13W3 connector, is an unusual connector that combines a 10-pin D-shell with three analog video conductors. It supports very-high-resolution analog video signals... more/see it nowand has been used by Sun Microsystems®, SGI, NeXt, Intergraph, and other manufacturers. Although 13W3 connectors from different manufacturers look the same, they may be pinned differently.
Pinning for a standard Sun® 13W3 connector:
2: Vertical Sync*
3: Sense 2
4: Sense Ground
5: Composite Sync
6: Horizontal Sync*
8: Sense 1
9: Sense 0
10: Composite Ground
* Considered obsolete; may not be connected. collapse
Black Box Explains...KVM tray technology.
KVM tray technology.
What we do that others don’t.
From the solid construction of our KVM trays, to unique features like LEDs on the ?front panel and integrated KVM switching, Black Box’s... more/see it nowKVM trays are miles ahead of the competition.
Nothing reduces clutter in a server room like KVM trays that are 1- or 2U high, and ?mount in a cabinet or rack. Here are some of the features that set our KVM trays apart.
TFT LCD support.
This type of monitor uses thin-film transistor (TFT) technology to improve image quality, resulting in higher resolutions, better image contrast, and addressability. All our KVM trays support TFT LCD panel monitors.
The screens on our KVM trays are viewable from nearly any angle. Because of the size of our screens, from 15" to 19", viewing angles vary from 140° x 120° all the way up to 160° x 160°, so you don’t always have to be standing directly in front of the monitor to see what’s happening on it.
Our ServTray Complete family of KVM trays (KVT417A-R2, etc.) has adjustable length instead of a variety of rear bracket sites. This universal rail rear bracket size fits racks with depths of 23.7" (60.2 cm) to 45.3" (115 cm). This simplifies ordering for you!
Dual rail technology.
This KVM tray technology enables the monitor drawer and the keyboard/mouse drawer to move independently of each other. It makes it easy to leave the monitor visible even when a server cabinet is closed and the keyboard/mouse drawer is fully retracted. Black Box has added switching controls to the monitor bezel that can be used to control an attached switch without pulling open the keyboard/mouse drawer for even more space-saving benefits.
Additionally, the dual rails provide a great monitoring environment without disturbing your cooling system.
You asked for it.
Our latest KVM trays, the ServView V KVM Drawer and ServView V KVM Drawer with Widescreen (KVT517A, etc.) were designed based on feedback we have received from some of our customers.
On the front panel of the tray, there is an LED panel, which helps you locate the ?drawer when it’s closed in a darkened data center. The tray only takes up 1U of rack space, and it features the dual rail technology described earlier.
We added front-panel controls for switching, so if you choose a model with an embedded KVM switch, you can use the buttons on the monitor bezel without pulling out the keyboard. Additionally, the top of the keyboard tray features a hideaway connection for USB wireless devices, such as RF- or Bluetooth® supported keyboards and mice. You can wirelessly access your attached targets, even without opening the cabinet door!
Another feature is the front-panel USB port, which provides crash cart access. If your keyboard or GlidePoint® mouse quit on you, simply use this port to attach a passthrough pointing device.
Finally, the widescreen version supports 1920 x 1080 resolutions and DVI connections — two firsts in the data center. collapse