Black Box Explains... SNMP.
SNMP (Simple Network Management Protocol) management is the standard for LAN management, particularly in mission-critical applications. The standard is controlled by the Internet Engineering Task Force (IETF). It was designed... more/see it nowto manage network configuration, performance, faults, accounting, and security.
An SNMP agent must be present at the device level (a router or a hub, for example), either built into the unit or as a proxy agent, and is accessed through a remote terminal. SNMP does not follow a polling protocol. It waits to receive data from the remote device or sends data based on operator commands.
By using one common set of standards, SNMP enables network administrators to manage, monitor, and control their SNMP-compliant network equipment with one management system and from one management station. If a network device goes down, it|s possible to both pinpoint and troubleshoot the problem more efficiently. And a network administrator isnt limited to equipment from just one vendor when using an SNMP program. 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...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 todays 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...vDSL.
VDSL (Very High Bit-Rate Digital Subscriber Line or Very High-Speed Digital Subscriber Line) is a “last-mile” broadband solution for both businesses and homes, providing economical, high-speed connections to fiber optic... more/see it nowbackbones.
VDSL enables the simultaneous transmission of voice, data, and video on existing voice-grade copper wires. Depending on the intended applications, you can set VDSL to run symmetrically or asymmetrically. VDSL’s high bandwidth allows for applications such as high-definition television, video-on-demand (VOD), high-quality videoconferencing, medical imaging, fast Internet access, and regular voice telephone services—all over a single voice-grade twisted pair. The actual VDSL distances you achieve vary based on line rate, gauge and type of wire, and noise/crosstalk environment.
Black Box Explains...Loose-tube vs. tight-buffered fiber optic cable.
There are two styles of fiber optic cable construction: loose tube and tight buffered. Both contain some type of strengthening member, such as aramid yarn, stainless steel wire strands, or... more/see it noweven gel-filled sleeves. But each is designed for very different environments.
Loose tube cables, the older of the two cable types, are specifically designed for harsh outdoor environments. They protect the fiber core, cladding, and coating by enclosing everything within semi-rigid protective sleeves or tubes. In loose-tube cables that hold more than one optical fiber, each individually sleeved core is bundled loosely within an all-encompassing outer jacket.
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 expand and contract with temperature changes, too.
But gel-filled loose-tube cables are not the best choice when cable needs to be submerged or where its routed around multiple bends. Excess cable strain can force fibers to emerge from the gel.
Tight-buffered cables, in contrast, are optimized for indoor applications. Because theyre sturdier than loose-tube cables, theyre best suited for moderate-length LAN/WAN connections, long indoor runs, and even direct burial. Tight-buffered cables are also recommended for underwater applications.
Instead of a gel layer or sleeve to protect the fiber core, tight-buffered cables use a two-layer coating. One is plastic; the other is waterproof acrylate. The acrylate coating keeps moisture away from the cable, like the gel-filled sleeves do for loose-tube cables. But this acrylate layer is bound tightly to the plastic fiber layer, so the core is never exposed (as it can be with gel-filled cables) when the cable is bent or compressed underwater.
Tight-buffered cables are also easier to install because theres no messy gel to clean up and they dont require a fan-out kit for splicing or termination. You can crimp connectors directly to each fiber.
Want the best of both worlds? Try a hybrid, breakout-style fiber optic cable, which combines tight-buffered cables within a loose-tube housing. collapse
Black Box Explains...DIN rails.
A DIN rail is an industry-standard metal rail, usually installed inside an electrical enclosure, which serves as a mount for small electrical devices specially designed for use with DIN rails.... more/see it nowThese devices snap right onto the rails, sometimes requiring a set screw, and are then wired together.
Many different devices are available for mounting on DIN rails: terminal blocks, interface converters, media converter switches, repeaters, surge protectors, PLCs, fuses, or power supplies, just to name a few.
DIN rails are a space-saving way to accommodate components. And because DIN rail devices are so easy to install, replace, maintain, and inspect, this is an exceptionally convenient system that has become very popular in recent years.
A standard DIN rail is 35-mm wide with raised-lip edges, its dimensions outlined by the Deutsche Institut für Normung, a German standardization body. Rails are generally available in aluminum or steel and may be cut for installation. Depending on the requirements of the mounted components, the rail may need to be grounded. collapse
Black Box Explains...HDBaseT
HDBaseT is a connectivity standard for distribution of uncompressed HD multimedia content. HDBaseT technology converges full HD digital video, audio, 100BaseT Ethernet, power over cable, and various control signals through... more/see it nowa single LAN cable. This is referred to as 5Play™, a feature set that sets HDBaseT technology above the current standard.
HDBaseT delivers full HD/3D and 2K/4K uncompressed video to a network of devices or to a single device (point-to-point). HDBaseT supports all key HDMI 1.4 features, including EPG, Consumer Electronic Controls (CEC), EDID, and HDCP. The unique video coding scheme ensure the highest video quality at zero latency.
As with the video, HDBaseT audio is passed through from the HDMI chipset. All standard formats are supported, including Dolby Digital, DTS, Dolby TrueHD, DTS HD-Master Audio.
HDBaseT supports 100Mb Ethernet, which enables communications between electronic devices including televisions, sound systems, computers, and more. Additionally, Ethernet support enables access to any stored multimedia content (such as video or music streaming).
HDBaseT's wide range of control options include CEC, RS-232, and infrared (IR). IP control is enabled through Ethernet channel support.
The same cable that delivers video, audio, Ethernet, and control can deliver up to 100W of DC power. This means users can place equipment where one wants to, not just those locations with an available power source.
HDBaseT sends video, audio, Ethernet, and control from the source to the display, but only transfers 100Mb of data from display to source (Ethernet and control data). The asymmetric nature of HDBaseT is based on a digital signal processing (DSP) engine and an application front end (AFE) architecture.
HDBaseT uses a proprietary version of Pulse Amplitude Modulation (PAM) technology, where digital data is represented as a coding scheme using different levels of DC voltage at high rates. This special coding provides a better transfer quality to some kinds of data without the need to "pay" the protecting overhead for the video content, which consumes most of the bandwidth. HDBaseT PAM technology enables the 5Play feature-set to be maintained over a single 330-foot (100 m) CAT cable without the electrical characteristics of the wire affecting performance.
Black Box Explains... Industrial modem benefits.
Not all modems shuttle data in air-conditioned, climate-controlled comfort. And modems that operate in cozy environments have absolutely no business being exposed to harsh industrial conditions or to the elements.
But... more/see it nowjust because you work in a rough-and-tumble place doesnt mean you have to sacrifice the convenience of a good modem. Instead, you should opt for an industrial modem. There are many industrial modems built for various degrees of extremity.
Survivability depends on reliability.
Sure, standard modems give you access to data in remote sites or enable you to service equipment on the plant floor—and you can do all this from the convenience of your office. However, these benefits are only possible if your modem can continue to function in its environment. And since standard modems arent built for adverse conditions, theyre not going to be reliable.
No penalties for interference.
Electrical control equipment—such as motors, relays, compressors, and generators—emit electromagnetic interference (EMI) that can affect the performance and reliability of a standard telephone modem.
EMI is emitted through power lines, the RS-232 communications cable, or through the telephone line itself. The very means of data communication, cable, is often the worst enemy of the standard modems that use it.
An industrial modem, on the other hand, has filters and superior EMI immunity to protect itself and your data. If you build your electrical cabinets to UL® or CSA standards, remember that your modem must also conform to UL® standard 508.
They go to extremes.
Temperature is the biggest killer of electronic equipment in industrial environments. The heat generated by industrial equipment in sealed enclosures or where space is a premium can make the temperature as much as 50 °F higher than the surrounding environment.
So standard modems cant take the heat. But what about being outdoors in the other extreme, cold weather? Well, standard modems cant take the cold either.
If you install your equipment in remote outdoor locations, it must work on the coldest days— especially those cold days when you least want to get in the car and go to the site to repair a standard modem that froze up.
Whether theyre placed in manufacturing environments or the great outdoors, industrial modems get the data through when you need it. They go to extremes for you.
Heavy metal for all kinds of banging around.
Industrial modems are built with durable metal enclosures that protect circuitry in rough conditions and ward off signal-disrupting EMI. Plus, they feature steel-bolt flanges to anchor them. In short, industrial modems can take the physical, heavy-duty punishment thrown their way.
So where exactly can you use an industrial modem?
• Heavy industry and manufacturing
• Oil and gas fields
• Storage sites
• Utility substations
• Agricultural projects
• Military facilities
• Research installations
• Water/wastewater systems
and another thing!
If dedicated copper lines cant be run through industrial environments, or if the fiber optic option is cost-prohibitive, there are also wireless industrial modems that make line-of-sight connections. If theres a way to get the data through, industrial modems will get the job done.
Industrial modems remain in service for a very long time. But if you ever need a replacement that is hardware or software compatible, be assured that Black Box continues to support its products year after year—so you don’t spend your time re-engineering systems if you have to make a replacement. collapse
Black Box Explains... Guidelines for choosing fiber optic cable.
Fiber optic cable is becoming one of the fastest-growing transmission mediums for both new cabling installations and upgrades, including backbone, horizontal, and even desktop applications. It’s favored for applications that... more/see it nowneed high bandwidth, long distances, and complete immunity to electrical interference.
It’s ideal for high-data-rate systems such as Gigabit Ethernet, FDDI, multimedia, ATM, SONET, Fibre Channel, or any other network that requires
the transfer of large, bandwidth-consuming data files, particularly over long distances.
Fiber offers the following advantages:
Greater bandwidth—Because fiber provides far greater bandwidth than copper and has proven performance at rates up to 10 Gbps, it gives network designers future-proofing capabilities as network speeds and requirements increase.
Also, fiber optic cable can carry more information with greater fidelity than copper wire. That’s why the telephone networks use fiber and many CATV companies are converting to fiber.
Low attenuation and greater distance—Because
the fiber optic signal is made of light, very little signal loss occurs during transmission, and data can move at higher speeds and greater distances. Fiber does not have the 100-meter (328-ft.) distance limitation of unshielded twisted-pair copper (without
a booster). Fiber distances can range from 300 meters (984.2 ft.) to 40 kilometers (24.8 mi.), depending on the style of cable, wavelength, and network. (Fiber distances are typically measured in metric units.) Because fiber signals need less boosting than
copper ones do, the cable performs better.
Security—Your data is safe with fiber cable. It doesn’t radiate signals and is extremely difficult to tap. If the cable is tapped, it’s very easy to monitor because the cable leaks light, causing the entire system to fail. If an attempt is made to break the physical security of your fiber system, you’ll know it.
Fiber networks also enable you to put all your electronics and hardware in one central location, instead of having wiring closets with equipment throughout the building.
Immunity and reliability—Fiber provides extremely reliable data transmission. It’s completely immune to many environmental factors that affect copper cable. The core is made of glass, which is an insulator, so no electric current can flow through. It’s immune to electromagnetic interference and radio-frequency interference (EMI/RFI), crosstalk, impedance problems, and more. You can run fiber cable next to industrial equipment without worry. Fiber is also less susceptible to temperature fluctuations than copper and can be submerged in water.
Design—Fiber is lightweight, thin, and more durable than copper cable. Plus, fiber optic cable has pulling specifications that are up to 10 times greater than copper cable’s. Its small size makes it easier to handle, and it takes up much less space in cabling ducts. Although fiber is still more difficult to terminate than copper, advancements in connectors are making termination easier. In addition, fiber is actually easier to test than copper cable.
Migration—The proliferation and lower costs of media converters are making copper to fiber migration much easier. The converters provide seamless links and enable the use of existing hardware. Fiber can be incorporated into networks in planned upgrades.
Standards—TIA/EIA standards are bringing fiber closer to the desktop. TIA/EIA-785, ratified in 2001, provides a cost-effective migration path from 10-Mbps Ethernet to 100-Mbps Fast Ethernet over fiber (100BASE-SX). An addendum to the standard eliminates limitations in transceiver designs. In addition, in June 2002, the IEEE approved a 10-Gigabit Ethernet (10-GbE) standard.
Costs—The cost for fiber cable, components, and hardware is steadily decreasing. Installation costs for fiber are higher than copper because of the skill needed for terminations. Overall, fiber is more expensive than copper in the short run, but it may actually be less expensive in the long run. Fiber typically costs less to maintain, has much less downtime, and requires less networking hardware. And fiber eliminates the need to recable for higher network performance.
Types of fiber cable and standards.
Multimode, 50- and 62.5-micron cable—Multimode
cable has a large-diameter core and multiple pathways of light. It comes in two core sizes: 50-micron and 62.5-micron.
Multimode fiber optic cable can be used for most general data and voice fiber applications, such as bringing fiber to the desktop, adding segments to an existing network, and in smaller applications such as alarm systems. Both 50- and 62.5-micron cable feature the same cladding diameter of 125 microns, but 50-micron fiber cable features a smaller core (the light-carrying portion of the fiber).
Although both can be used in the same way, 50-micron cable is recommended for premise applications (backbone, horizontal, and intrabuilding connections) and should be considered for any new construction and installations. Both also use either LED or laser light sources. The big difference between the two is that 50-micron cable provides longer link lengths and/or higher speeds, particularly in the 850-nm wavelength.
Single-mode, 8–10-micron cable—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. Consequently, single-mode cable is typically used 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 for up to twice the throughput of multimode fiber. collapse