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...The 13W3 connector.
The 13W3 connector, also called a 13C3 or DB13W3 connector, is an unusual connector that combines a 10-pin D-shell with three analog video conductors. It supports very-high-resolution analog video signals... more/see it nowand has been used by Sun Microsystems®, SGI, NeXt, Intergraph, and other manufacturers. Although 13W3 connectors from different manufacturers look the same, they may be pinned differently.
Pinning for a standard Sun® 13W3 connector:
2: Vertical Sync*
3: Sense 2
4: Sense Ground
5: Composite Sync
6: Horizontal Sync*
8: Sense 1
9: Sense 0
10: Composite Ground
* Considered obsolete; may not be connected. collapse
Black Box Explains...Token Ring Cabling
The original Token Ring specifications called for shielded twisted-pair (STP) cable using either a DB9 connector or a unique square connector called the IBM data connector. Later, Token Ring was... more/see it nowadapted to use conventional unshielded twisted-pair (UTP) cable with RJ-45 connectors. The most common kinds of Token Ring cabling in use to day are Type 1 and Type 6 STP as well as Type 3 UTP.
Type 1 shielded twisted-pair (STP) cable is the original wiring for Token Ring. In Type 1 cabling, each wire is constructed of 22 AWG solid copper. Type 1 cable is not as flexible as Type 6 cable and is generally used for long runs in areas where twists and turns are less likely, such as in walls or conduits.
Type 6 Token Ring cable is a lighter, more pliable version of Type 1 cable. It’s constructed of two stranded 26 AWG copper pairs that are surrounded by an overall braided shield. Type 6 cable is commonly used in offices and open areas, and its flexible construction enables it to negotiate multiple twists and turns.
Type 3 or UTP Token Ring cabling uses the same twisted-pair CAT3, CAT5, or CAT5e cabling with RJ-45 connectors as 10BASE-T Ethernet does. Attaching older Type 1 Token Ring to UTP Token Ring requires a balun or adapter. collapse
Black Box Explains... SCSI termination
This is the oldest method of termination. A passive terminator sits on the bus to minimize reflections at the end of the cable. Passive terminators simply provide impedance close... more/see it nowto that of the cable. The terminator is “passive” because it doesnt do any work to regulate power for termination; it relies on the interface card to provide steady power.
This is a more stable form of terminating SCSI cables. Active terminators control the impedance at the end of the SCSI bus by using a voltage regulator, not just the power supplied by the interface card.
Of all SCSI terminators, this is the most complex. A cable with a forced-perfect terminator can actually change its impedance to compensate for variations along the bus. Forced-perfect terminators force the impedance of the cable to match each device through diode switching and biasing. collapse
Black Box Explains...Optical isolation and ground loops.
Optical isolation protects your equipment from dangerous ground loops. A ground loop is a current across a conductor, created by a difference in potential between two grounded points, as in... more/see it nowequipment in two buildings connected by a run of RS-232 or other data line. When two devices are connected and their potentials are different, voltage flows from high to low by traveling through the data cable. If the voltage potential is large enough, your equipment wont be able to handle the excess voltage and one of your ports will be damaged.
Ground loops can also exist in industrial environments. They can be created when power is supplied to your equipment from different transformers or when someone simply turns equipment on and off. Ground loops can also occur when there is a nearby lightning strike. During an electrical storm, the ground at one location can be charged differently than the other location, causing a heavy current flow through the serial communication lines that damage components.
You cant test for ground loops. You dont know you have one until a vital component fails. Only prevention works. For data communication involving copper cable, optical isolation is key.
With optical isolation, electrical data is converted to an optical beam, then back to an electrical pulse. Because there is no electrical connection between the DTE and DCE sides, an optical isolator unlike a surge suppressorwill not pass large sustained power surges through to your equipment. Since data only passes through the optical isolator, your equipment is protected against ground loops and other power surges. collapse
Black Box Explains...Flexible microphones.
A headset featuring a flexible, swing-away microphone boom is easy to adjust—all you need to do is bend the boom until the microphone is in the correct position. Plus, you... more/see it nowcan easily swing the microphone out of your way if you wish to take a sip of coffee or soda while you’re on the phone. collapse
Black Box Explains... Buffers
A buffer (also called a spooler or a cache) is a temporary storage device used to share printers and compensate for a difference in speed and data flow between two... more/see it nowdevices. Buffers use RAM (Random-Access Memory) to take in data and hold it until the receiving device handles it.
A buffer serving a computer can be installed either internally or externally. Internal computer buffers are common in the forms of keyboard inputs, data caches, and video memory. An external buffer is usually used for printing.
An external buffer downloads jobs to the printer, freeing the computer so you can get back to work sooner.
A print buffers ports can be serial, parallel, or serial and parallel. Because a buffers ports operate independently of each other, a buffer also can be made to perform serial-to-parallel or parallel-to-serial conversion or to change the word structure and/or serial data rate (baud rate) of the data.
While most buffers are FIFO (First In, First Out), some advanced units can function as random-access buffers. For most serial buffers, hardware flow control is required, but some also support software (X-ON/X-OFF) control. Most buffers support printing of multiple copies of a document, provided the buffer has enough memory to store the entire print job. collapse
Black Box Explains...Industrial Ethernet (Ethernet/IP) and IP-rated connectors.
Ethernet technology is coming to the factory floor. Once limited to office environments, Ethernet has proven to be a robust alternative to the RS-232 interface traditionally used with industrial devices... more/see it nowsuch as programmable logic controllers. Ethernet brings speed, versatility, and cost savings to industrial environments.
The requirements of industrial environments are different than offices, so there are industrial Ethernet standards. The most common is the Ethernet/Industrial Protocol (Ethernet/IP) standard, usually called Industrial Ethernet. Industrial Ethernet adapts ordinary, off-the-shelf IEEE 802.3 Ethernet communication chips and physical media to industrial applications.
The Ingress Protection (IP) ratings developed by the European Committee for Electrotechnical Standardization (CENELEC) specify the environmental protection an enclosure provides.
An IP rating consists of two or three numbers. The first number refers to protection from solid objects or materials; the second number refers to protection from liquids; and the third number, commonly omitted from the rating, refers to protection against mechanical impacts. An IP67 rating means that a connector is totally protected from dust and from the effects of immersion in 5.9 inches (15 cm) to 3.2 feet (1 m) of water for 30 minutes.
Because office-grade RJ-45 connectors do not stand up to an industrial environment, the Ethernet/IP standard calls for sealed industrial RJ-45 connectors that meet an IP67 standard, meaning the connectors are sealed against dust and water. 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