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Black Box Explains...Connectors.



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Black Box Explains...Cable termination.


Carefully remove the jacketing from the cable and expose one inch of the insulated wire conductors. Do not remove any insulation from the conductors. When the... more/see it nowRJ-45 connector is crimped, the contacts inside will pierce the conductor insulation.


Untwist the wires to within 1/8" of the jacket. Arrange the wires according to the cable spec (568B in this case). Flatten and align the wires. Make one straight cut across all the conductors, removing approximately 1/2" to ensure the ends are of equal length.


Slide the wires into a connector. The cable jacket should extend into the connector about 1/4" for strain relief. Orient the wires so connector Pin 1 aligns with cable Pin 1, etc. Hold the connector in front of you. With the locking tab down, Pin 1 is on the far left.


Insert the connector into a crimp tool. Make sure you’re using the proper die. Firmly squeeze the handles. They’ll lock in a ratcheting action. A final click indicates the connector is firmly latched.


Check your work using a continuity tester or cable certifier rated for the cable standard you’re installing. Your tester should be able to check for shorts, opens, or miswires.


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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


Using optical break locators and OTDRs.

An optical time-domain reflectometer, or OTDR, is an instrument used to analyze optical fiber. It sends a series of light pulses into the fiber under test and analyzes the light... more/see it nowthat is scattered and reflected back. These reflections are caused by faults such as breaks, splices, connectors, and adapters along the length of the fiber. The OTDR is able to estimate the overall length, attenuation or loss, and distance to faults. It’s also able to “see” past many of these “events” and display the results. The user is then able to see all the events along the length of the fiber run.

However, OTDRs do have a weakness?—?a blind spot that prevents them from seeing faults in the beginning of the fiber cable under test. To compensate for this, fiber launch boxes are used. Launch boxes come in predetermined lengths and connector types. These lengths of fiber enable you to compensate for this blind spot and analyze the length of fiber without missing any faults that may be in the first 10–30 meters of the cable.

An optical break locator, or OBL, is a simplified version of an OTDR. It’s able to detect high-loss events in the fiber such as breaks and determine the distance to the break. OBLs are much simpler to use than an OTDR and require no special training. However, there are limitations. They can only see to the first fault or event and do not display information on the portion of fiber after this event. collapse


Black Box Explains...Choosing cabinets and racks.



Why cabinets? Why racks?


A cabinet is an enclosure with a door (or doors); a rack is an open frame. There are several things you... more/see it nowshould consider when you’re deciding whether you need an enclosed cabinet or a rack.


First, what equipment will you be putting in it? The extra stability of a cabinet might be important if you’re installing large, heavy equipment like servers. But if you need frequent access to all sides of the equipment, an open rack might be more convenient. And if your equipment needs a lot of ventilation, you’ll have to be more careful about the air supply if you enclose it in a cabinet.


Second, in what environment will you be installing it? If the environment is open or dusty, for example, you might need the extra protection of an enclosed cabinet. On the other hand, a rack might be perfectly adequate in a well-maintained data center.


Don’t neglect aesthetics. Will customers or clients see your installation? A cabinet with a door looks much neater than an open rack. When you’re trying to create a professional image, everything counts.


Finally, there’s security. An enclosed cabinet can be locked with a simple lock and key.


On the other hand, there are advantages to open racks, too. It’s easier to get at all sides of the equipment. But you’ll have to take other steps to keep the equipment secure-keeping it in a locked room, for example.


Both cabinets and racks come in all sizes and in many different installation styles. Some are freestanding; some are designed to be mounted on a wall. Others sit on the floor but attach to the wall for more stability.


If you need to set up your installation in a hurry, you can order a preassembled cabinet. You’re ready to load your equipment as soon as the cabinet arrives.


Choosing the right server cabinet.

Consider this quick checklist of features when choosing a server cabinet:

  • High-volume airflow. The requirements for additional airflow increase as more servers are mounted in a cabinet. Additionally, manufacturers are making servers narrower to increase available space. But with more servers in the same amount of space, heat buildup is frequently a problem.
  • Extra depth to accommodate newer, deeper servers.
  • Adjustable rails.
  • Rails with M6 square holes. Although 10-32 tapped and drilled holes are sometimes still required, newer hardware has M6 square holes. Know which type of mounting equipment you’ll need.
  • Front and/or rear accessibility.
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 with 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 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.


Choosing the right rack.

Before you choose a rack, you have to determine what equipment you need to house. This list can include CPUs, monitors, keyboards, modems, servers, switches, hubs, routers, and UPSs. Consider the size and weight of all your equipment as well. The rack must be large and strong enough to hold everything you have now, and you’ll also want to leave extra room for growth.

Most racks are designed to hold equipment that’s 19" (48.3 cm) wide. But height and depth may vary from rack to rack. Common rack heights range from 39" (99.1 cm) to 87" (221 cm).


Another measurement you should know about is the rack unit. One rack unit, abbreviated as U, equals 1.75" (4.4 cm). A rack that is 20U, for example, has 20 rack spaces for equipment, or is 35" high (88.9 cm).


Understanding cabinet and rack measurements.

The main component of a cabinet or rack is a set of vertical rails with mounting holes to which you attach your equipment or shelves. When you consider the width or height of the rack, clarify whether they are inside or outside dimensions.

The first measurement you need to know is the width between the rails. The most common size is 19 inches with hole-to-hole centers measuring 18.3 inches. But there are also 23-inch and 24-inch cabinets and racks. Most rackmount equipment is made to fit 19-inch rails but can be adapted to fit wider rails.


After the width, the most important specification is the number of rack units, abbreviated “U.” It’s a measurement of vertical space available on the rails. Because the width is standard, the amount of vertical space is what determines how much equipment you can actually install. Remember that this measurement of usable vertical space is smaller than the external height of the cabinet or rack.


One rack unit (1U) is 1.75 inches of usable vertical space. So, for example, a rackmount device that’s 2U high will take up 3.5 inches of rack space. A rack that’s 20U high will have 35 inches of usable space.

Because both racks and the equipment that fit in them are usually measured in rack units, it’s easy to figure out how much equipment you can fit in a given cabinet or rack.



Do you need a fan?

Even if your cabinet or rack is in a climate-controlled room, the equipment in it can generate a lot of heat. You may want to consider adding a fan to help keep your equipment from overheating. It’s especially important to have adequate ventilation in an enclosed cabinet.


Getting power to your equipment.

Unless you want to live in a forest of extension cords, you’ll need one or more power strips. Some cabinets come with power strips built in.


If you need to order a power strip, consider which kind will be best for your installation. Rackmount power strips come in versions that mount either vertically or horizontally. Some have outlets that are spaced widely to accommodate transformer blocks-a useful feature if your equipment uses bulky power transformers.


Surge protection is another important issue. Some power strips have built-in surge protection; some don’t. With all the money you have invested in rackmount equipment, you’ll certainly want to make sure it’s protected.


Any mission-critical equipment should also be connected to an uninterruptible power supply (UPS). A UPS keeps your equipment from crashing during a brief blackout or brownout and gives you enough time to shut down everything properly in an extended power outage. You can choose a rackmount UPS for the most critical equipment, or you can plug the whole rack into a standalone UPS.


Managing the cables.

Your equipment may look very tidy when it’s neatly stacked in a cabinet. But you still have an opportunity to make a mess once you start connecting it all. Unless you’re very careful with your cables, you can create a rat’s nest you’ll never be able to sort out.


There are many cabinet and rack accessories that can simplify cable organization. We have Cable Management Guides, Rackmount Cable Raceways, Horizontal Covered Organizers, Vertical Cable Organizers, Horizontal Wire Ring Panels, and Cable Manager Hangers-all designed to help you manage your cables more easily.


Plotting your connections in advance helps you to decide how to organize the cables. Knowing where the connectors are on your equipment tells you where it’s most efficient to run cables horizontally and where it’s better to run them vertically.

The important thing is to have a plan. Most network problems are in the cabling, so if you let your cables get away from you now, you’re sure to pay for it down the road.


Asking for help.

When you’re setting up a cabinet or rack, you have a lot of different factors to consider. Black Box Tech Support is always happy to help you figure out what you need and how to put it together. For cabinets and racks solutions, call our Connectivity Group at 724-746-5500, press 1, 2, 2.

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Black Box Explains...Thermocouples

A thermocouple is a device that measures temperature by using the fact that a junction between two different metals produces a varying voltage related to their temperature. Two common types... more/see it nowof thermocouple are Type J and Type K.

Type J thermocouples use iron paired with a nickel-copper alloy. Type J thermocouples may cover a temperature range of up to -40 to +1382° F (-40 to +750°C), and offer high sensitivity.

Type K, the most common type of thermocouple, uses nickel-chromium and nickel-aluminum alloys. Because Type K is an early specification, its characteristics vary widely; individual thermocouples may cover a range of up to -328 to +2462 °F (-200 to +1350 °C). collapse


Black Box Explains…Terminating fiber.

Terminating fiber cable used to be a job for experts only. But today, prepolished connectors make it possible for anyone to terminate multimode fiber—all you need is a bit of... more/see it nowpatience and the right tools. Here’s how to terminate fiber with ST connectors:

Step 1 — Slide the connector strain-relief boot, small end first, onto the cable.

Step 2 — Using a template, mark the jacket dimensions to be stripped (40 mm and 52 mm from the end).

Step 3 — Remove the outer jacket from the cable end to the 40 mm mark. Cut the exposed Kevlar. Carefully remove the jacket to the 52-mm mark, exposing the remaining length of Kevlar.

Step 4 — Fan out the Kevlar fibers and slide the crimp ring of the connector approximately 5 mm over the fibers to hold them out of the way. Mark the fiber buffer 11 mm from the end of the cable jacket. Also, mark the buffer where it meets the jacket.

Step 5 — Bit by bit, strip off the buffering until you reach the 11-mm mark. Check the mark you made on the buffer at the jacket. If it’s moved, carefully work the buffer back into the jacket to its original position.

Step 6 — Clean the glass fiber with an alcohol wipe. Cleave the fiber to an 8-mm length.

Step 7 — Carefully insert the fiber into the connector until you feel it bottom out and a bow forms between the connector and the clamp. Cam the connector with the appropriate tool.

Step 8 — Crimp the connector.

Step 9 — Slide the crimp ring up the jacket away from the connector, releasing the Kevlar fibers. Fan the fiber so they encircle the buffer. The ends of the fibers should just touch the rear of the connector—if they’re too long, trim them now.

Step 10 — Crimp the connector again.

Step 11 — Slide the strain-relief boot over the rear of the connector. You might want to put a bead of 411 Loctite adhesive for extra strength on the rear of the boot where it meets the jacket.

Although the details may vary slightly with different connectors and termination kits, the basic termination procedure is the same. collapse


Black Box Explains...Link loss.

Media converters solve the problem of connecting different media types in mixed-media networks. In order to comply with IEEE standards, they implement IEEE data-encoding rules and the Link Integrity Test.

For... more/see it nowa twisted-pair segment, a link is a signal sent by the converters when the cable is in use. If no Link Integrity Test signal is received, the connected device assumes that the link is lost.

With fiber cable, a connected device checks a line by monitoring the Link Integrity Test signal from the converter and the power of the light being received. If the light’s power drops below a certain threshold, the link is lost. In either case, link loss usually results from a broken cable, which is the cause of approximately 70% of all LAN problems.

Link loss is often indicated by an LED on a connected network device. You can also monitor a link with network-management software, such as SNMP, which sends a TRAP (alert) to the management workstation when the link is lost.

Media converters actually function as two separate Multistation Access Units (MAUs). For example, one monitor is a twisted-pair segment and one monitor is a fiber segment. If a fiber cable is broken and the link is lost, a network manager on the twisted-pair end won’t know there’s a problem until users on the fiber side report it.

To solve this problem, Black Box® Modular Media Converters feature a unique Link-Loss capability. This enables the link status on one segment to reflect the link status of the other segment. So if the link is lost on the fiber side, the link is disabled on the UTP segment as well. And the converters will send an SNMP TRAP indicating the loss of link to the management workstation. collapse


Mounting flat-screen displays.

Traditionally, computer monitors, TVs, or other video displays have simply been placed on a shelf or desktop. However, today’s flat screens are less stable than older vacuum-tube displays and should... more/see it nowbe secured to prevent tipping. Fortunately, most new displays meet the VESA standard, meaning they have a hole pattern on the back that fits any VESA standard mounting device such as a wall mount, desktop mount, or ceiling mount. This enables you to secure the display to prevent damage from accidental jolts and bumps. Additionally, a mounted display is less likely to be the object of theft. collapse

  • Pdf Drawing... 
  • HD Adapter Panel, with (8) Duplex MT-RJ Pairs, PDF Drawing
    PDF Drawing for the JPM416A-R2
 
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