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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...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: M1 connectors.

In 2001, the Video Electronics Standards Association (VESA) approved the M1 Display Interface System for digital displays. The M1 system is a versatile and convenient system designed for computer displays,... more/see it nowspecifically digital projectors. M1 supports both analog and digital signals.

M1 is basically a modified DVI connector that can support DVI, VGA, USB and IEEE-1394 signals. The single connector replaces multiple connectors on projectors. An M1 cable can also be used to power accessories, such as interface cards for PDAs.

There are three primary types of M1 connectors:
–M1-DA (digital and analog). This is the most common connector, and it supports VGA, USB and DVI signals.
–M1-D (digital) supports DVI signals.
–M1-A (analog) supports VGA signals.

The M1 standard does not cover any signal specifications or detailed connector specifications. collapse


Black Box Explains...DDS vs. T1.

DDS (Digital Data Service) is an AT&T® service that transmits data digitally over dedicated leased lines. DDS lines use four wires, and support speeds up to 56 kbps; however, DDS... more/see it nowis actually a 64-kbps circuit with 8 kbps being used for signaling. You can also get 64-kbps (ClearChannel™) service. Since the transmission is digital, no modems are needed. Dedicated digital lines are ideal for point-to-point links in wide-area networks.

T1 is a dedicated transmission line operating at 1.544 Mbps. It’s comprised of 24 DSOs, each supporting speeds of 64 kbps. The user sends data at N x 56 or N x 64 over T1 circuits. T1 operates over twisted-pair cable and is suitable for voice, data, and image transmissions on long-distance networks. collapse


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 isn’t limited to equipment from just one vendor when using an SNMP program. collapse


Black Box Explains... Multiplatform cabling environments.

When using a ServSwitch™ with multiple computer platforms, choosing which peripherals to use to control your diverse group of CPUs can be confusing. Because of the wide variation in connector... more/see it nowtypes and compatibilities, there is a hierarchy to follow when choosing your “user station“ keyboard, monitor, and mouse.

1. If you have at least one Sun® computer in your application, you should use a Sun keyboard and mouse to control your CPUs.

2. If you have a mixture of PCs and Mac® computers, use your PC-style keyboard and mouse to control your CPUs. collapse


Black Box Explains...Code-operated and matrix switches.

Code-operated and matrix switches from Black Box give you computer-controlled switching for a variety of applications.

Code-operated switches
BLACK BOX® Code-Operated Switches enable one device to control up to 64 connected devices,... more/see it nowdepending on the code-operated switch. For instance, you can use one modem—not eight—to control eight devices. Code-operated switches are ideal for applications that require remote switching for file sharing or monitoring. Use code-operated switches for:
• Remote programming. Call in via remote sites to access servers, logic controllers, or any devices that require programming.
• Diagnostics. From your master control room, you can probe servers and run diagnostics.

Matrix switches
Matrix switches enable more than one device to control other devices. Any port can connect to any port and perform more than one operation at a time independently. The code-operated switches talk to only one slave port at a time.

For instance, if your operation has four computers that need to share two printers and one modem, a matrix switch is what you need to handle the job. Use matrix switches for:
• Industrial applications. You can download instructions remotely to more than one programmable logic controller.
• Data sharing. PCs or industrial devices can be connected—locally or remotely—to other PCs and industrial devices or for file swapping. collapse


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...802.3ah.

802.3ah, also called Ethernet in the First Mile (EFM), is a new Ethernet standard designed to compete with standards such as DSL and cable modem in delivering broadband access to... more/see it nowhomes.

The 802.3ah specification covers point-to-point copper, point-to-point fiber, and point-to-multipoint fiber.

Ethernet in the First Mile over Copper (EFMC)
This point-to-point specification for copper wire takes advantage of DSL technology to send Ethernet over one pair of copper wires at 10 Mbps for 750 meters or 2 Mbps for 2700 meters.

Ethernet in the First Mile over Fiber (EFMF)
This point-to-point specification for single-mode, single-strand or single-mode, duplex fiber sends Ethernet at speeds of 100 Mbps or 1 Gbps up to 10 kilometers. It includes an optional extended temperature range from -40 to 185° F (-40 to 85° C) for outdoor use.

Ethernet in the First Mile over Passive Optical Networks (EPON)
This point-to-multipoint specification for fiber uses an optical splitter to divide the Ethernet signal into separate strands that go to individual subscribers. This enables an ISP to link many subscribers to a single uplink fiber without using active components in the field.

802.3ah includes the OAM specification, which provides utilities for monitoring and troubleshooting Ethernet links remotely, a capability vital for carrier-class deployment. OAM protocols address discovery, link monitoring, remote fault signaling, and remote loopback.

OAM is managed in-band but takes up very little bandwidth so network performance is not noticeably affected. OAM itself is not affected by VLANs or port-access restrictions. collapse


Black Box Explains...V.35, the Faster Serial Interface.

V.35 is the ITU (formerly CCITT) standard termed “Data Transmission at 48 kbps Using 60–108 KHz Group-Band Circuits.“

Basically, V.35 is a high-speed serial interface designed to support both higher data... more/see it nowrates and connectivity between DTEs (data-terminal equipment) or DCEs (data-communication equipment) over digital lines.

Recognizable by its blocky, 34-pin connector, V.35 combines the bandwidth of several telephone circuits to provide the high-speed interface between a DTE or DCE and a CSU/DSU (Channel Service Unit/Data Service Unit).

Although it’s commonly used to support speeds ranging anywhere from 48 to 64 kbps, much higher rates are possible. For instance, maximum V.35 cable distances can theoretically range up to 4000 feet (1200 m) at speeds up to 100 kbps. Actual distances will depend on your equipment and cable.

To achieve such high speeds and great distances, V.35 combines both balanced and unbalanced voltage signals on the same interface. collapse

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