Black Box Explains... ServSwitch Multi and audio cable.
Get more out of your ServSwitch Multi. Add audio cable, a set of speakers, and a microphone to each CPU. Audio cable turns your ServSwitch Multi into the ideal system... more/see it nowfor education, training, retail, medical, and multimedia office environments.
Audio cable isnt just for the ServSwitch Multi either. You can also use it with servers that give off audible alarms.
So even if you dont have audio equipment now—plan ahead. When youre ready to add audio equipment, just plug in our audio cable. collapse
Black Box Explains...Shielded vs. unshielded cable.
The environment determines whether cable should be shielded or unshielded.
Shielding is the sheath surrounding and protecting the cable wires from electromagnetic leakage and interference. Sources of this electromagnetic activity... more/see it now(EMI)—commonly referred to as noise—include elevator motors, fluorescent lights, generators, air conditioners, and photocopiers. To protect data in areas with high EMI, choose a shielded cable.
Foil is the most basic cable shield, but a copper-braid shield provides more protection. Shielding also protects cables from rodent damage. Use a foil-shielded cable in busy office or retail environments. For industrial environments, you might want to choose a copper-braid shield.
For quiet office environments, choose unshielded cable. collapse
Black Box Explains...IEEE 1284
Introduced in 1994, the IEEE 1284 standard addresses data-transfer speeds and distance for parallel interfaces. Standard parallel interfaces support speeds of up to 150 kbps at distances of up to... more/see it now6 feet (1.8 m); IEEE 1284 parallel interfaces can send your data over 100 times faster at up to five times the distance!
Although the Centronics® interface enabled only unidirectional computer-to-peripheral data flow, the IEEE 1284 interface enables bidirectional flow so peripherals can send data to the computer.
The IEEE 1284 standard covers five separate parallel modes, from the original Centronics (with which it’s compatible) to the high-performance Enhanced Parallel Port (EPP) mode. The computer negotiates with the attached device to determine which mode to use. 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.
Black Box Explains...Terminal Servers
A terminal server (sometimes called a serial server) is a hardware device that enables you to connect serial devices across a network.
Terminal servers acquired their name because they were originally... more/see it nowused for long-distance connection of dumb terminals to large mainframe systems such as VAX™. Today, the name terminal server refers to a device that connects any serial device to a network, usually Ethernet. In this day of network-ready devices, terminal servers are not as common as they used to be, but they’re still frequently used for applications such as remote connection of PLCs, sensors, or automatic teller machines.
The primary advantage of terminal servers is that they save you the cost of running separate RS-232 devices. By using a network, you can connect serial devices even over very long distances—as far as your network stretches. It’s even possible to connect serial devices across the Internet. A terminal server connects the remote serial device to the network, and then another terminal server somewhere else on the network connects to the other serial device.
Terminal servers act as virtual serial ports by providing the appropriate connectors for serial data and also by grouping serial data in both directions into Ethernet TCP/IP packets. This conversion enables you to connect serial devices across Ethernet without the need for software changes.
Because terminal servers send data across a network, security is a consideration. If your network is isolated, you can get by with an inexpensive terminal server that has few or no security functions. If, however, you’re using a terminal server to make network connections across a network that’s also an Internet subnet, you should look for a terminal server that offers extensive security features. collapse
Black Box Explains...Controlling GPIO interfaces with iCOMPEL.
With the iCOMPEL™, interactivity goes beyond touchscreen support. It also supports general-purpose input/output (GPIO) capabilities. Through an external device with a GPIO interface, the playing of on-screen information can be... more/see it nowtriggered (or halted) by signals originating from device inputs via contact closures. These can be external infrared motion detectors, light sensors, switches, push buttons, building control systems—even external SCADA collection systems.
The possibilities are endless. You can set up a screen to provide emergency notification during crises—based on a signal sent when a secure door is opened or when an environmental condition occurs. Or simply use a screen to welcome visitors walking through your main door. You can even have a screen change from a static display to an interactive touchscreen when someone approaches.
Just connect the external device to the iCOMPEL using our ICOMP-GPIO Adapter, which adapts the USB port on the iCOMPEL to a DB9 (RS-232) port. (NOTE: Older iCOMPEL units include a DB9 port, so the adapter isn’t needed.) This adapted port can be used for sending user-defined RS-232 strings and receiving RS-232 strings. The port also offers four input lines for binary events, such as motion detection, contact closure, or other device signaling. In some cases, you can even use the RS-232 connection to power simple detection devices.
Each RS-232 input item can be included in a playlist and used to generate an Advance To or Change Layout on a user-defined transition of the line. The Advance To or Change Layout commands can be configured to change the media being played by the iCOMPEL.
The iCOMPEL has the ability to control the output state of the RS-232 DTR and RTS lines. The lines are controlled by RS-232 output items, which can appear as items in the iCOMPEL playlist menu. The RS-232 output items can assign the state of one or both RS-232 output lines and optionally a string of characters to be output.
For further details on how to activate touchscreen and contact closure capabilities on an iCOMPEL unit, contact our FREE Tech Support. Our experts can also recommend accessories for motion detection and other GPIO-controlled functions.
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…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…Sizing a UPS
The power delivered by a UPS is usually expressed both in volt-amps (VA) and watts. There’s often confusion about what the difference is between these figures and how to use... more/see it nowthem to select a UPS.
VA is power voltage multiplied by amps. For instance, a device that draws 5 amps of 120-volt power has a VA of 600. Watts is a measure of the actual power used by the device. VA and watts may be the same. The formula for watts is often expressed as:
Watts = Volts x Amps
This formula would lead you to believe that a measurement of VA is equal to watts, and it’s true for DC power. AC power, however, can get complicated. Some AC devices have a VA that’s higher than watts. VA is the power a device seems to be consuming, while watts is the power it actually uses.
This requires an adjustment called a power factor, which is the ratio of watts to VA.
AC Watts = Volts x Amps x Power Factor
Watts/VA = Power Factor
Simple AC devices, such as light bulbs, typically have a power factor of 100% (which may also be expressed as 1), meaning that watts are equal to VA like they are with DC devices. Computers have had a much lower power factor, traditionally in the 60–70% range. This meant that only part of the power going into the computer was being used to do useful work.
Today, however, because of Energy Star requirements, virtually all computing devices are power factor corrected and have a power factor of more than 90%.
Which brings us around to how to use this information to select a UPS. The capacity of a UPS is defined as both VA and watts. Both should be above the power requirements of the connected equipment.
Because of the computers that had a low power factor, UPSs typically had a VA that was much higher than watts, for instance, 500 VA/300 watts. In this case, if you use the UPS with a power factor corrected device that requires 450 VA/400 watts, the UPS won’t provide enough wattage to support the device.
Although UPSs intended for enterprise use now normally have a high power factor, consumer-grade UPSs still typically have a lower power factor—sometimes even under 60%. When using these UPSs, size them by watts, not VA, to ensure that they can support connected equipment.
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.