Loading


Content Type (x) > Black Box Explains (x)

Results 91-100 of 208 << < 6 7 8 9 10 > >> 

Black Box Explains...Serial ATA technology.

Introduced in the mid 1980s, the Advanced Technology Attachment (ATA) interconnect soon became the industry-standard parallel input/output bus interface for connecting internal storage devices. Ultra ATA, which builds on the... more/see it noworiginal parallel ATA interface, has become the most commonly used type of interconnect.

But in recent years, sharing digital video and audio files over high-speed networks and other data-intensive uses has placed greater demands on hard drives, optical drives, and media-storage peripherals. So, not surprisingly, Ultra ATA now faces competition from a new technology—Serial ATA.

As the name implies, this new interconnect uses a serial bus architecture instead of a parallel one. Serial ATA currently supports speeds up to 150 MBps. Further enhancements could to boost rates as high as 600 MBps.

Compared with Ultra ATA, Serial ATA offers distinct advantages, including a point-to-point topology that enables you to dedicate 150 MBps to each connected device. Each channel can work independently and, unlike the “master-slave” shared bus of Ultra ATA, there’s no drive contention or interface bandwidth sharing.

Compared with Ultra ATA’s parallel bus design, Serial ATA requires a single signal path for sending data bits and a second path for receiving acknowledgement data. Each path travels across a 2-wire differential pair, and the bus contains four signal lines per channel. Fewer interface signals means the interconnect cable requires less board space.

Serial ATA also uses thinner cables (no more than 0.25" wide) that are available in longer lengths (up to 1 meter) as well as an improved connector design to reduce crosstalk. It also offers hot-swappable capabilities.

Although Serial ATA can’t interface directly with earlier Ultra ATA devices, it complies fully with the ATA protocol, so software between the two interconnects is compatible. collapse


Black Box Explains...Advantages of fiber optic line drivers.

Fiber optic line drivers are much better for communications than copper-wire alternatives because they offer three main advantages: superior conductivity, freedom from interference, and security.

Superior conductivity for increased performance
The glass... more/see it nowcore of a fiber optic cable is an excellent signal conductor. With proper splices and terminations, fiber cable yields very low signal loss and can easily support data rates of 100 Mbps or more.

Immunity to electrical interference
Because fiber optic line drivers use a nonmetallic conductor, they don’t pick up or emit electromagnetic or radio-frequency interference (EMI/RFI). Crosstalk (interference from an adjacent communication channel) is also eliminated, which increases transmission quality.

Signals transmitted via fiber optic line drivers aren’t susceptible to any form of external frequency-related interference. That makes fiber connections completely immune to damaging power surges, signal distortions from nearby lightning strikes, and high-voltage interference. Because fiber cable doesn’t conduct electricity, it can’t create electrical problems in your equipment.

Signal security
Electronic eavesdropping requires the ability to intercept and monitor the electromagnetic frequencies of signals traveling over a copper data wire. Fiber optic line drivers use a light-based transmission medium, so they’re completely immune to electronic bugging. 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.

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...Choosing the right headset.

Black Box offers several headsets for office use. Choosing the right one for your application depends on your needs.

First, do you need a monaural, binaural, or stereo headset? Monaural headsets... more/see it nowhave only one earpiece, making it easy to have over-the-phone conversations as well as face-to-face interactions, such as in a busy call center setting (see models HS402 or 64338-31, for example). Binaural headsets have two earpieces, which are on the same audio channel (HS113A or 2009-820-105). They are great when a user needs to have long, over-the-phone conversations. Stereo headpieces also have two earpieces, but operate on distinct audio channels. These last types of earpieces are best for listening to music.

Secondly, comfort is a big factor, especially if you have to wear a headset all day. Do you want an over-the-head model? Or would you prefer to wear your headset behind the ear? Headsets with two earpieces are almost always over-the-head models (see H16N). For long-wear applications and optimum sound quality, these are a good choice. Over-the-ear models are better for in-office interactions, or for when you are on and off the phone all day (26089-11 or M140). The sound quality is still excellent, but they enable you to also be aware of your environment.

Thirdly, choose an amplifier that matches your telephone and the way you work. The Two-Prong Carbon Amplifier (HS101A) is designed for phones that have a two-prong headset port. Several headsets have amplifiers built-in, such as the Elite Call Center Headset (HS111A).

Most Black Box headsets are noise-canceling models that reduce background sounds. They are ideal for busy office environments.

We have wireless headset models, plus cords, plugs, and adapters that enable extra mobility during calls. In addition, we carry extra parts such as earhooks, ear pads, headbands, and microphone covers. collapse


Black Box Explains...Coax connectors.

The BNC (Bayonet-Neill-Concelman) connector is the most commonly used coax connector. This large ”bayonet“ connector features a slotted outer conductor and an inner plastic dielectric, and it offers easy connection... more/see it nowand disconnection. After insertion, the plug is turned, tightening the pins in the socket. It is widely used in video and Radio Frequency (RF) applications up to 2.4 GHz. It is also common in 10BASE2 Ethernet networks, on cable interconnections, network cards, and test equipment.

The TNC connector is a threaded version of the BNC connector. It works in frequencies up to 12 GHz. It‘s commonly used in cellular telephone RF/antenna applications.

The N connector is a larger, threaded connector that was designed in the 1940s for military systems operating at less than 5 GHz. In the 1960s, improvements raised performance to 12 GHz. The connector features an internal gasket and is hand tightened. It is common on 2.4-GHz antennas.

The UHF connector looks like a coarse-threaded, big center-conductor version of the N connector. It was developed in the 1930s. It is suitable for use up to 200–300 MHz and generally offers nonconstant impedance.

The F connector is most often used in cable and satellite TV and antenna applications; and it performs well at high frequencies. The connector has a 3/8–32 coupling thread. Some F connectors are also available in a screw-on style.

The SMA (Subminiature A) connector is one of the most common RF/microwave connectors. This small, threaded connector is used on small cables that won’t be connected and disconnected often. It’s designed for use to 12.4 GHz, but works well at 18, and sometimes even up to 24 GHz. This connector is often used in avionics, radar, and microwave communications.

The SMC (Subminiature C) connector is a small, screw-on version of the SMA. It uses a 10–32 threaded interface and can be used in frequencies up to 10 GHz. This connector is used primarily in microwave environments.

The SMB (Subminiature B) connector is a small version of the SMC connector. It was developed in the 1960s and features a snap-on coupling for fast connections. It features a self-centering outer spring and overlapping dielectric. It is rated from 2–4 GHZ, but can possibly work up to 10 GHz.

The MCX (Micro Coax) connector is a coax RF connector developed in the 1980s. It has a snap-on interface and uses the same inner contact and insulator as the SMB connector but is 30% smaller. It can be used in broadband applications up to 6 GHz. collapse


Black Box Explains...NEMA 12 certification.

The National Electrical Manufacturers’ Association (NEMA) specifies guidelines for cabinet certifications. NEMA 12 cabinets are constructed for indoor use to provide protection against certain contaminants that might come in contact... more/see it nowwith the enclosed equipment. The NEMA 12 designation means a particular cabinet has met the guidelines, which include protection against falling dirt, circulating dust, lint, fibers, and dripping or splashing non-corrosive liquids. Protection against oil and coolant seepage is also a prerequisite for NEMA 12 certification.

Organizations with mission-critical equipment benefit from a NEMA 12 cabinet. Certain environments put equipment at a higher risk than others. For example, equipment in industrial plants is subject to varying degrees of extreme temperature. Even office buildings generate lots of dust and moisture, which is detrimental to equipment. NEMA 12 enclosures help to ensure that your operation suffers from as little downtime as possible. collapse


Black Box Explains... Manual switch chassis styles.

There are five manual switch chassis styles: three for standalone switches (Styles A, B, and C) and two for rackmount switches (Styles D and E). Below are the specifications for... more/see it noweach style.

Standalone Switches

Chassis Style A
Size — 2.5"H x 6"W x 6.3"D (6.4 x 15.2 x 16 cm
Weight — 1.5 lb. (0.7 kg)
Chassis Style B
Size — 3.5"H x 6"W x 6.3"D (8.9 x 15.2 x 16 cm)
Weight — 1.5 lb. (0.7 kg)
Chassis Style C
Size — 3.5"H x 17"W x 5.9"D (8.9 x 43.2 x 15 cm)
Weight — 8.4 lb. (3.8 kg)

Rackmount Switches

Chassis Style D (Mini Chassis)
Size — 3.5"H x 19"W x 5.9"D (8.9 x 48.3 x 15 cm)
Chassis Style E (Standard Chassis)
Size — 7"H x 19"W x 5.9"D (17.8 x 48.3 x 15 cm) collapse


Black Box Explains... Why go wireless?

• It’s great for communicating in harsh climates or in areas where it’s expensive to run cable. Wireless solutions are well suited for use in military applications, farming, refineries, mining,... more/see it nowconstruction, and field research.
• Because sometimes you just can’t run wire, like in historic buildings or hazmat areas.
• When it’s physically or legally impossible to support conventional hard-wired RS-232 communications, wireless networking may be your only answer.
• It gives you quick, temporary connections at trade shows, and fast reconfigurations—even troubleshooting or remote field testing.
• It provides reliable disaster relief when all else fails! Count on wireless networks to maintain mission-critical links when disaster strikes.
• It’s more affordable, more reliable, and faster than ever before.
• Best of all, no FCC licensing required! collapse


Black Box Explains...Choosing a wireless antenna.


Ride the wave.

One of the most critical components to operating a successful wireless network is having the right antennas. Antennas come in many different shapes and sizes,... more/see it noweach designed for a specific function. Selecting the right antennas for your network is crucial to achieving optimum network performance. In addition, using the right antennas can decrease your networking costs since you’ll need fewer antennas and access points.


Basically, a wireless network consists of data, voice, and video information packets being transmitted over low-frequency radio waves instead of electrically over copper cable or via light over fiber lines. The antenna acts as a radiator and transmits waves through the air, just like radio and TV stations. Antennas also receive the waves from the air and transport them to the receiver, which is a radio, TV, or in the case of wireless networking, a router or an access point.


Type cast.

The type of antennas you use depends on what type of network you’re setting up and the coverage you need. How large is your network? Is it for a home, single office, campus, or larger? Is it point-to-point or multipoint?


The physical design-walls, floors, etc.- of the building(s) you’re working in also affects the type and number of antennas you need. In addition, physical terrain affects your antenna choices. Obviously, a clear line of sight works best, but you need to consider obstructions such as trees, buildings, hills, and water. (Radio waves travel faster over land than water.) You even need to consider traffic noise in urban settings.


The ideal shape.

Let’s take a look at the different types of antennas.


Isotropic Antenna. First, think of the introduction to the old RKO movies. A huge tower sits on top of the world and emanates circular waves in all directions. If you could actually see the waves, they would form a perfect sphere around the tower. This type of antenna is called an isotropic antenna, and does not exist in the real world. It is theoretical and is used as a base point for measuring actual antennas.


Go in the right direction.

Now let’s turn to real-world antennas. There are many types of antennas that emit radio waves in different directions, shapes, and on different planes. Think of the spherical isotropic antenna. If squeezed from the sides, it will become shaped like a wheel and will concentrate waves on a vertical plane. If squeezed from the top, it will flatten out like a pancake and radiate waves on a horizontal plane. Thus, there are two basic types of antennas: directional and omnidirectional.


Directional antennas.

Directional antennas, primarily used in point-to-point networks, concentrate the waves in one direction much like a flashlight concentrates light in a narrow beam. Directional antennas include backfire, Yagi, dish, panel, and sector.


Backfire. This small directional antenna looks like a cake pan with a tin can in the middle. It’s designed to be compact, often under 11" in diameter, making it unobtrusive and practical for outdoor use. These antennas also offer excellent gain, and can be used in both point-to-point or point-to-multipoint systems.


Yagi. The Yagi-Uda (or Yagi) antenna is named for its Japanese inventors. The antenna was originally intended for radio use and is now frequently used in 802.11 wireless systems.


A Yagi antenna is highly directional. It looks like a long fishbone with a central spine and perpendicular rods or discs at specified intervals. Yagi antennas offer superior gain and highly vertical directionality. The longer the Yagi, the more focused its radiation is. Many outdoor Yagi antennas are covered in PVC so you can’t see the inner structure.


Yagi antennas are good for making point-to-point links in long narrow areas (for instance, connecting to a distant point in a valley) or for point-to-point links between buildings. They can also be used to extend the range of a point-to-multipoint network.


Parabolic or Dish. These antennas look like a circular or rectangular concave bowl or "dish". The backboard can be solid or a grid design. Parabolic grid designs are excellent for outdoor use since the wind blows right through them. The concave nature of this dish design focuses energy into a narrow beam that can travel long distances, even up to several miles. This makes parabolic antennas ideal for point-to-point network connections. Since they generate a narrow beam in both the horizontal and vertical planes, offer excellent gain, and minimize interference, they’re ideal for long-distance point-to-point networks.


Panel or Patch. These antennas are often square or rectangular, and they’re frequently hung on walls. They’re designed to radiate horizontally forward and to the side, but not behind them. Sometimes they’re called "picture-frame" antennas.


Panel antennas are ideal in applications where the access point is at one end of a building. They’re good for penetrating a single floor of a building, and for small and medium-size homes and offices. Since they might not have much vertical radiation, they might not be a good choice for multifloor applications.


Because panel antennas can be easily concealed, they’re a good choice when aesthetics are important.


Sector. A sector antenna can be any type of antenna that directs the radio waves in a specific area. They are often large, outdoor flat-panel or dish-type antennas mounted up high and tilted downward toward the ground. These antennas are often used in sprawling campus settings to cover large areas.


Omnidirectional antennas.

Omnidirectional antennas provide the widest coverage possible and are generally used in point-to-multipoint networks. Their range can be extended by overlapping circles of coverage from multiple access points. Most omnidirectional antennas emanate waves in a fan-shaped pattern on a horizontal plane. Overall, omnidirectional antennas have lower gain than directional antennas. Examples of omnidirectional antennas include: integrated, blade, and ceiling.


Integrated. Integrated antennas are antennas that are built into wireless networking devices. They may be embedded in PC card client adapters or in the covers or body of laptops or other devices, such as access points. Integrated antennas often do not offer the same reception as external antennas and might not pick up weak signals. Access points with integral antennas must often be moved or tilted to get the best reception.


Blade. These small, omnidirectional antennas are often housed in long, thin envelopes of plastic. They are most often used to pick up a signal in a low-signal or no-signal spot. You usually will see them on the walls of cubicles, mounted on desktops, or even hung above cubicles to catch signals. They’re basically an inexpensive signal booster.


Ceiling Dome. These are sometimes also called ceiling blister antennas. They look somewhat like a smoke detector and are designed for unobtrusive use in ceilings, particularly drop ceilings. Ceiling dome antennas often have a pigtail for easy connection to access points. They’re excellent for use in corporate environments where wide coverage over a cube farm is needed.


Wave basics.

To better understand wireless antennas and networking, there are some basic measurements and terms that need to be discussed.


Gain. One of the primary measurements of antennas is gain. Gain is measured as dBi, which is how much the antenna increases the transmitter’s power compared to the theoretical isotropic antenna, which has a gain of 0 dBi. dBi is the true gain the antenna provides to the transmitter’s output. Gain is also reciprocal-it’s the same transmitting and receiving. Higher gain means stronger sent and received signals. An easy way to remember gain basics is that every 3 dB of gain added doubles the effective power output of an antenna. The more an antenna concentrates a signal, the higher the gain it will have.


You can actually calculate the gains and losses of a system by adding up the gains and losses of its parts in decibels.


Frequency and Wavelength. Electromagnetic waves are comprised of two components: frequency and wavelength.


Frequency is how many waves occur each second. Wavelength is the distance between one peak of a wave and the next peak. Lower frequencies have longer wavelengths; higher frequencies have shorter wavelengths. For example, the frequency of AM radio is 1 MHz with a wavelength of about 1000 feet. FM radios operate at a much higher frequency of 100 MHz and have a wavelength of about 100 feet.


The two most common frequencies for wireless networking are 2.4-GHz and 5-GHz. Both are very high frequencies with very short wavelengths in the microwave band. The 2.4-GHz frequency has a wavelength of about 5 inches.


Beamwidth. Consider an antenna to be like a flashlight or spotlight. It reflects and directs the light (or radio waves) in a particular direction. Beamwidth actually measures how energy is focused or concentrated.


Polarization. This is the direction in which the antenna radiates wavelengths, either vertically, horizontally, or circularly. Vertical antennas have vertical polarization and are the most common. For optimum performance, it is important that the sending and receiving antennas have the same polarization.


VSWR and Return Loss. Voltage Standing Wave Ratio (VSWR) measures how well the antenna is matched to the network at the operating frequency being used. It indicates how much of the received signal won’t reach either the transceiver or receiver. Return loss measures how well matched an antenna is to the network. Typical VSWR numbers are 1:1.2 or 1:1.5. A typical return loss number is 20.

collapse

Results 91-100 of 208 << < 6 7 8 9 10 > >> 
Close

Support

Delivering superior technical support is our highest priority. Depending on the products or services we provide for you, please visit your appropriate support area.



 
Print
Black Box 1-877-877-2269 Black Box Network Services