Firewire

With more than 30 times the bandwidth of the popular USB 1.1 peripheral standard, FireWire 400 has been the gold standard for high-speed data transfer. Apple was the first computer manufacturer to include FireWire across its entire product line. And now Apple has upped the ante yet again, effectively doubling data throughput with its implementation of the IEEE 1394b standard, FireWire 800

FireWire 400 vs. USB 1.x
FireWire and USB have both found their place in the computer and consumer electronics industries. USB is the technology of choice for most computer mice, keyboards and other lower bandwidth input devices. FireWire, with its higher bandwidth, longer distances and much higher-powered bus — is more suitable for such applications as digital video (DV), professional audio, hard drives, high-end digital still cameras and home entertainment devices.

How fast is 1394?
The 1394 standard defines three signaling rates which, in precise terms, are: 98.304, 196.608 and 393.216 Mbits/s (megabits per second). These rates are referred to in the 1394 standard as S100, S200 and S400. The 1394b specification (finalized in early 2002) expands the standard to include 800 and 1,200 Mbits/s speeds. You can mix and match devices of different speeds on the same bus. Using "isochronous" data transmission, even the S100 implementation supports two simultaneous channels of 30fps (frames per second) broadcast-quality video along with stereo audio.

How does 1394 compare to SCSI?
The SCSI bus requires that devices be serially daisy-chained together, with each device having a non-conflicting, pre-assigned address and that the final SCSI device be terminated. There is a limit of seven devices on a SCSI chain. In contrast, 1394 devices can be connected in multiple configurations. These can include a star or tree pattern with its own daisy chain branches. Device terminators are not required. And 1394 addressing, unlike SCSI, is done dynamically; there is no need for address pre-assignment. Plus, 1394 allows up to 1,023 buses to be bridged together.

How does 1394 compare to Ethernet?
1394 multiplexes (combines) a variety of different types of digital signals, including video, audio, MIDI and device control commands, on two twisted-pair conductors (similar to that of 10base-T Ethernet). This ability to easily multiplex or combine different signal types distinguishes 1394 from other systems which transmit only a single signal type.

Ethernet, for example, is typically used in data networks and requires special protocols (presently implemented only in proprietary multimedia networking systems) to transmit real-time, high-quality audio and video.

In comparison, 1394 is much more flexible in its accommodation of different data types and topologies than Ethernet and other alternative networking systems. 1394 uses a "fairness" arbitration approach to assure that all devices that have information to transmit get a chance to use the bus. 1394 protocols also include device-specific commands to start and stop camcorders, VCRs and other tasks. Standard Ethernet does not provide these important features.

What is hot swapping?
Hot swapping is the connection and disconnection of computer peripherals or other components while a system is turned on, without interrupting system operation. 1394 enables hot swapping.

• Strip the cables Jacket back one full inch.
• Untwist the wires back to within 1/8" of the jacket.
• Arrange the wires in the order in which you want to crimp them. You can choose from either the 568-A or 568-B wiring methods, however the 568-B is the most commonly used.
• Grasp the wires firmly, between your thumb and forefinger, flatten them, and even wiggle them a bit, to take out the curliness, (concentrate your efforts on the bottom 1/2") the wires must lay flat and together, aligned as close as possible.
• While holding the wires firmly, cut off the the wires 1/2" from the cables jacket (Cut the wires with some sharp wire strippers or even high quality scissors, avoid wire cutters that flatten the ends of the wires insulating material, this makes stuffing the wires very difficult.)
• Stuff the wires into the connector, making sure the wires stay lined up. Push moderately hard to assure that all of the wires have reached the end of the connector. Be sure that the cable jacket goes into the back of the connector by about 3/16".
• Place the connector into a crimp tool, and squeeze hard so that the handle reaches it's full swing.
• Repeat the process on the other end. For a straight through cable, use the same wiring.
• Use a cable tester to test for proper continuity

How to wire a CAT5 (EIA 568-B*) Cable.

connector #1	connector #2
1 WHT/ORG 2 ORG/WHT 3 WHT/GRN 4 BLU/WHT 5 WHT/BLU 6 GRN/WHT 7 WHT/BRN 8 BRN/WHT	1 WHT/ORG 2 ORG/WHT 3 WHT/GRN 4 BLU/WHT 5 WHT/BLU 6 GRN/WHT 7 WHT/BRN 8 BRN/WHT

How to wire a CAT5 (EIA 568-A*) Cable.

connector #1	connector #2
1 WHT/GRN 2 GRN/WHT 3 WHT/ORG 4 BLU/WHT 5 WHT/BLU 6 ORG/WHT 7 WHT/BRN 8 BRN/WHT	1 WHT/GRN 2 GRN/WHT 3 WHT/ORG 4 BLU/WHT 5 WHT/BLU 6 ORG/WHT 7 WHT/BRN 8 BRN/WHT

The only real difference between 568A and 568B is that
the White/Orange-Orange/White and White/Green-Green/White pairs are swapped.

How to wire a "Crossover" Cable. (EIA 568-B*)

connector #1	connector #2
1 WHT/ORG 2 ORG/WHT 3 WHT/GRN 4 BLU/WHT 5 WHT/BLU 6 GRN/WHT 7 WHT/BRN 8 BRN/WHT	1 WHT/GRN 2 GRN/WHT 3 WHT/ORG 4 BLU/WHT 5 WHT/BLU 6 ORG/WHT 7 BRN/WHT 8 WHT/BRN

.

USB

 

The Universal Serial Bus or USB cable was developed around the idea that users should be able to run multiple peripherals on their computers without the hassle of physically installing boards, manually allocating system resources, individually configuring devices, and powering the computer up and down every time equipment needs change. With USB cable, up to 127 individual peripheral devices can be connected to a host computer using a single interface and a system of USB hubs. (See below for a diagram of a typical USB system.) Attaching a USB peripheral to your computer is as easy as plugging headphones into your Walkman. USB devices are automatically recognized and configured. They can draw power directly from the system, from an attached self-powered hub, or be connected to their own power supply.

USB Cable Features

USB provides two-way communication between the PC and peripheral devices, making it ideal for many I/O applications. Multiple devices can connect to a system using a series of USB hubs and repeaters. A single USB interface is attached to the motherboard. A Root Hub with up to seven additional ports can be integrated into the main interface, or it can be externally connected with a cable. Each of the seven hubs on the Root Hub can in turn be connected to seven hubs, etc. to a maximum of seven tiers and 127 ports. A unique feature of USB is that a peripheral device can have a hub built into it. This type of peripheral, called "compound devices," are comprised of a function device and one or more hubs. For example, a USB keyboard can contain an additional USB port for a USB mouse.

USB is generally described as having a tiered star topology, however each device communicates with the host as if it had its own connection. This means that communication from the host centers around a set of hubs/devices, each of which in-turn serves as the center for another set of hubs/devices, etc. However, the hubs are transparent to the software and the devices are addressed individually. Cables are used to create point-to-point connections between devices and USB ports, or to connect one USB hub to another. The maximum cable length is five meters long. However, a repeater hub may be used to extend the distance between the peripheral and the host. There are also special USB repeaters that can be used to extend the connection even further.

USB Cables and Ports

The Root USB Hub is connected directly to the USB Host, and from there everything is done with cables. Two types of USB cables can be used with USB devices: Series A and Series B. Series B cables are limited to 3 meters in length and are for use with low-speed (1.5 Mbps) USB peripherals such as keyboards and mice. The UTP cable has a pair of 28 AWG wire stranded copper for data and one pair 20-28 AWG for power.

The Series A connector is for use with high speed (12 Mbps) devices, and can be up to 5 meters long. The more common of the two, it consists of one pair 20-28 AWG wire for power (VBUS is typically +5V at the source) and one 28 AWG twisted wire pair for data. The connector has a shielded housing, making it STP compliant.

USB Cable Power Management

One special feature of USB systems is that they can directly supply power to the peripherals and the hubs attached to them. It can also regulate power usage for peripherals that use independent power sources. USB devices are classified based on the amount of power they supply or require. Low Bus Power devices take all their power from the bus, but no more than 100mA at a time. High bus-powered devices also take all their power from the bus, but can draw up to 500mA at a time. Self-powered devices use an external power supply, but can draw up to 1mA from the host if necessary--such as in the case of a power failure.

Hubs can also be low, high or self powered. Power flows downstream in a USB system, which means that a self-powered hub can be used to power high- and low-powered peripheral devices located further down in the network. This power arrangement has both advantages and disadvantages. For desktop systems where power is not a problem, it is extremely convenient not to have to use a separate outlet for each peripheral connected to the PC. In notebooks where battery longevity is often a problem, it might be more advantageous to use peripheral devices that have their own power source.

USB 2.0

USB Specification 1.1 was designed for low to medium speed applications running at less then 12 Mbits/sec. As such it is not suited for high-end data transfer such as high-speed back-ups to hard disks or CDs , high resolution color printing and interactive gaming. The recently released USB Specification 2.0 aims to upgrade the bus for high performance applications. The main difference between Specification 1.1 and 2.0 is that the latter provides for data transfer rates up to 480 Mbits/sec.

USB 2.0 is fully backward compatible with all older USB devices. It merely adds another device class--"high speed device." The USB host controller determines the type of devices attached to it, and then treats them accordingly. In fact, a high-speed USB hub can be used for both high, full (12Mbps) and low (1.5Mbps) speed devices at the same time.

USBB adapters will remain USB 1.1 devices, as even the fastest serial communication is limited to 10Mbps--well within the range of a full speed device.

USB for Data Communication

For low to medium speed data communication applications USB Specification 1.1 provides a clear usability advantage older bus types. USB peripherals are both Plug and Play and Hot Swappable devices. Further, USB cable is flexible enough to incorporate up to 127 individual devices into a single system using only one interface. And, unlike PCMCIA cards, where the board itself is subject to considerable wear from multiple insertions and extractions, USB devices use a connector cable which can be inserted and removed multiple times without consequence. Because of USB's structure, it can potentially reduce system downtime considerably.

As a bus option designed for both desktop and portable use, USB can bridge the gap between desktop and portable peripherals, provided the new peripherals are designed in small enough form to be practical for portable systems, and provided they do not draw too heavily from a laptop's limited battery power.

USB 2.0 with its considerably higher speeds rivals both board-level interfaces such as PCI and other interfaces such as Firewire. In fact, some computer companies are pushing for a PC standard that will no longer supply slots for plug-in boards, and will rely completely on USB and Firewire type devices.

USB's major drawback is its inability to implement peripherals designed for older protocols. As USB popularity increases, it is becoming more likely that a USB device exists for any given application. However, software applications written for non-USB peripherals cannot be implemented using USB because of the difference in communication protocols. Quatech has solved this problem with our FreedomUSB serial adapters. With Quatech's FreedomUSB Series you can take full advantage of USB benefits while continuing to use your current serial peripherals in your existing applications.

A keystone jack is a female connector used in data communications, particularly local area networks (LANs). A keystone jack is usually mounted in a wall plate or patch panel. A keystone plug is the matching male connector, usually attached to the end of a cable or cord that is inserted into the jack for data communications.

A principal advantage of keystone connectors is their versatility. Several types of keystone jack can be mounted on a single patch panel. They are available in CAT3, CAT5e, and CAT6; in either shielded or unshielded forms. Keystone Jacks can also accommodate cords and cables having various numbers of conductors.

The term keystone derives from the characteristic shape of the jack, resembling the standard RJ-11 wall jack used to connect telephone sets, fax machines, and dial-up computer modems to conventional telephone lines.

1. Contacts are 50 microinches gold plating over 100 microinches nickel on phosphor bronze.
2. 110 or Krone type IDC termination for 22-26 AWG solid wire.
3. Color coded termination for easy identification and installation. Available on both T568A and T568B wiring.
4. 9 color choice of body provides great options for color designation of the port.
5. Dust caps/retention caps over termination provide strain relief.
6. Supplied with color coded dust cover to stop foreign objects or dust.

HDMI Cable

1) What is the difference between Dual Link and Single Link?Which do I need?

Dual link enables a higher resolution (1920 X 1080) and more channels. You can view 2 displays simultaniously. If in doubt, order the Dual Link cable because it is backwards compatible with Single Link.

2) I need a DVI-I to DVI-D cable - What part number do I buy?

A DVI-I enables digital and analog signals. A DVI-D only allows digital signals. The part number to buy is DVIDL-length

3) Why are your DVI cables so much less?

You are coming right to the source. Our cables meet all wiring specifications. We don't know why everybody else is so expensive.

4) Is there a distance limitation?

Yes. For digital DVI cables there is a 5 Meter distance limitation. If you go longer the video results will be unpredictable and not guaranteed.

5) What is the TFT LCD?

TFT stands for "Thin Film Transistor" and describes the control elements that actively control the individual pixels. For this reason, one speaks of so-called "active matrix TFT's". LCD means "Liquid Crystal Display" and stands for monitors that are based on liquid crystals.

6) What's the difference between CRTs size and TFT size?

The visible diagonal size of a CRT tub monitor is always smaller than the tube's actual diagonal size. For example: a 17-inch CRT monitor has an edge area and it's visible diagonal is only 16-inches. But TFT LCD monitors do not have an edge area. This means that a 15-inch TFT LCD monitor is almost the same as the 17-inch CRT monitor.

7) What's the Contrast Ratio?

The Contrast Ratio is derived from the maximum and the minimum values for brightness.

8) What's the difference netween Digital and Analog Interface? Any advantages or disadvantages?

TFT LCD monitors with an analog VGA interface dominate the market. Because it is easy to install PC basis and not purchase a new graphics board. Although digital TFT LCD monitors don't need to adjust clock and phase and the no signal losses advantage. The Digital Interface standard has totally different connectors and it is not easy to buy a suitable graphic board. So the analog TFT LCD monitors still dominate the market. The following table gived you an overview of the most important points:

Digital Control

Advantages
 

No signal losses due to DA and AD conversion

Geometry, clock and phase settings unnecessary - therefore simple to use

Lower costs as less electronic circuitry required

 

Disadvantages
 

Currently three standards (P & D (M1DA), DFP, and DVI)

Low availability of models with digital interfaces

Requires graphic board with digital output

 

Analog Control

Advantages
 

Compatible with standard VGA boards on a broad installed PC basis

Not necessary to purchase seperate board

 

Disadvantages
 

Clock and phase of the TFTs must be synchronized with the analog signal to avoid pixel jitter, which is a relatively complex issue

Cables sensitive to external influences

High cost of signal conversion inside the display

Upgrade to digital interface not possible