USB 1.1
The Universal Serial Bus is the most widely deployed PC peripheral interface in history, enabling simple plug and play connectivity for a wide variety of devices to enhance the computing experience. Developed to improve ease of use and provide flexible port expansion, the USB bus has become an indispensable computing technology. USB 1.1 provides support for two interface speeds: Low Speed at 1.5Mb/s and Full Speed at 12Mb/s. The two interface speeds target specific classes of devices to provide the most efficient and cost-effective interconnect solution. Low speed devices are typically interactive input devices such as keyboards, mice or game controllers. Full speed devices are typically application specific input devices such as microphones, cameras and printers. Despite the introduction of USB 2.0 and 3.0, USB 1.1 is still a very viable and usable option, depending on your application and speed requirements.
USB 2.0
The Universal Serial Bus is the most widely deployed PC peripheral interface in history, enabling simple plug and play connectivity for a wide variety of devices to enhance the computing experience. As PC’s and peripheral devices have added more processing bandwidth, performance and features, the USB 2.0 standard was developed to offer a complimentary high-speed transfer rate at 480Mb/s. Backwards compatible with the full speed and low speed transfer rates of USB 1.1, USB 2.0 delivers a significant bandwidth increase while maintaining the value added features that motivated the original USB development.
Super Speed USB 3.0
As technology innovation marches forward, new kinds of devices, media formats, and large inexpensive storage are converging. They require significantly more bus bandwidth to maintain the interactive experience users have come to expect. In addition, user applications demand a higher performance connection between the PC and these increasingly sophisticated peripherals. USB 3.0 addresses this need by adding an even higher transfer rate to match these new usage and devices.
USB continues to be the answer to conncectivity for PC, Consumer Electronics, and Mobile architectures, It is a fast, bidirectional, low-cost, dynamically attachable interface that is consistent with the requirements of the PC platforms of today and tomorrow.
SuperSpeed USB brings significant performance enhancements to the ubiquitous USB standard, while remaining compatible with the billions of USB enabled devices currently deployed in the market. SuperSpeed USB will deliver 10x the data transfer rate of Hi-Speed USB, as well as improved power efficiency.
• SuperSpeed USB has a 5 Gbps signaling rate offering 10x performance increase over Hi-Speed USB.
• SuperSpeed USB is a Sync-N-Go technology that minimizes user wait-time.
• SuperSpeed USB will provide Optimized Power Efficiency.No device polling and lower active and idle power requirements.
• SuperSpeed USB is backwards compatible with USB 2.0. Devices interoperate with USB 2.0 platforms. Hosts support USB 2.0 legacy devices.
The USB 3.0 SuperSpeed specification has been ratified. The SuperSpeed specification provides the technical details to understand USB 3.0 requirements and design USB 3.0 compatible products and is available for download from the official USB website at www.usb.org/developers/docs/.
Check our MilesTek’s complete line of USB products, http://www.milestek.com/search.asp?skw=ZZAVD
RG6 Quad shield and RG6 Dual shield are pretty much identical in terms of signal loss. However, when it comes to rejecting interference, Quad is far superior and should be used in high EMI environments. If there is absolutely no chance of interference, Dual would be fine.
Check out MilesTek’s offering of RG59 and RG6 coaxial cables:
http://www.milestek.com/lp_coax_cable.asp
The first obvious difference between RG59 and RG6 is the diameter of the cables themselves. Standard RG59 coax has a 20 AWG copper center conductor and RG6 coax has an larger 18 AWG copper center conductor, offering higher bandwidth and longer distance capability.
Generally, RG6 is widely used in CATV and Satellite DSS applications and RG59 is used for in analog CCTV or baseband video applications. RG6 Dual or Quad Shield shouldn’t be utilized for baseband applications, such as video projectors, component video, plasma TV’s, etc. It may sound like a great solution because of all the layers of shielding, but RG6 Dual and Quad Shield don’t have the proper type of shielding for the above described applications. It is manufactured using foil shields and braided aluminum shields. The makeup of the shields differs between models. The effective range of operation for foil shields is above 50MHz, which makes them perfect for rejection of radio frequency interference, or RFI, that may have an effect on satellite or cable installations. At frequencies below 50 MHz, however, foil shields are not effective. The braiding on the RG6 Dual shield and the RG6 Quad shield doesn’t have enough coverage to work effectively with baseband applications.
The frequencies that are used in High Definition are usually around 37 MHz. For those lower frequencies, an RG59 with a 95% all-copper shield is designed to block RFI inclusion at base band frequencies. Because RG59 does not have a foil shield, it shouldn’t be utilized for satellite feeds or cable feeds.
RG59 has a little less signal reduction, or attenuation, over 100 feet. The shielding on RG59 does not work quite as well to maintain Gigahertz level signals inside of the center conductor. RG6 has a better design for maintaining the signal levels inside the center conductor. This is the reason RG6 has become the standard for broadband CATV and satellite systems. A basic rule of thumb is to use RG6 for any Rapid Frequencies, and use RG59 for video frequencies. RG6 has an aluminum braid and an aluminum shield. RG59 comes with a copper braid, and in some instances, an aluminum braid and shield, although this is quite rare.
Check out MilesTek’s offering of RG59 and RG6 coaxial cables:
http://www.milestek.com/lp_coax_cable.asp
The traditional usage of 50 Ohm BNC connectors on 75 Ohm cable in analog video and analog telephony central office equipment has little distortion effect on the signal at frequencies below 300 MHz.
However, digital signals in video and telephony applications have necessitated the usage of 75 Ohm connectors with 75 Ohm cable. Mismatched connectors cause attenuation of the digital signal resulting in slower rise time of square waves. This distortion of the signal can cause transmission errors. Also, impedance mismatched connections cause reflections of the signal returning to the source known as return loss. Perhaps one mismatched connection will not have a noticeable effect on system performance, but multiple mismatched connections in the link between the source and destination have a cumulative effect causing possible distortion of the transmitted signal.
Is the quality of MilesTek BNC’s the same as other brands?
Depending on the brand, MilesTek BNC’s are equal to or exceed the quality of other competitors. For example, the MilesTek BNC plug bodies are machined from virgin brass in accordance with MIL-C39012 and then plated with bright nickel. Many other less expensive brands have cheaper die cast bodies. Furthermore, the MilesTek BNC body incorporates a beryllium copper wave washer to allow the BNC to flex during mating and to provide firm uninterruptible continuity of the shield signal. Teflon, the best dielectric, provides the proper dielectric for 75Ω impedance and securely holds the captive center pin.
How is your BNC center pin different than some other brands?
In order to be true 75Ω impedance, the center pin has the same diameter in the crimp area as the mating area. Our captive BNC pins are plated with 30 µ” of gold in accordance with MIL-G-45204. More than 30 µ” is unnecessary for normal use. Some competitive brands have a 75Ω body with 50Ω center pin to eliminate the necessity of a separate center pin crimper. If tested, the connector with 50Ω pin and 75Ω body produces an impedance of approximately 68Ω .
Should the BNC body have enclosed beryllium copper spring fingers?
One manufacturer promotes this idea. Unless the BNC is subject to abuse such as thousands of matings and foreign objects poking into the interface of the connector, this design is unnecessary.
What about cable pull strength?
Pull strength is important on small diameter cables such as 735A. MilesTek BNC plugs have diamond knurling for maximum cable retention. Out of 3,000 to 4,000 coaxial cable assemblies, MilesTek’s BNC’s for 735A recorded pull test performance of 49.3 Ibs. The minimum specification is 30 Ibs.
Since the early datacom years (circa 1984), baluns (BALanced-Unbalanced) have played a key role in the migration from coax-based cabling systems to structured twisted pair cabling systems (SCS). In fact, the largest adopter of unshielded twisted pair (UTP) technology today is the Ethernet LAN industry. Prior to 10/100BaseT becoming a standard, companies such as MuxLab were developing baluns to adapt earlier Ethernet cabling standards (10Base5 and 10Base2) to unshielded twisted pair.
A balun is basic cabling device that interfaces with a structured cabling system, providing the essential link between traditional coax-based equipment and copper twisted pair cable. Its importance lies in its relative simplicity and its ability to passively or actively connect a wide range of data/video equipment to a pre-existing copper twisted pair cabling infrastructure, thereby overcoming the inherent limitations of UTP and preserving the investment in the cabling system. Over the past ten (10) years balun technology has started to make inroads into the traditional audio-video arena. Today balun technology is having a major impact on the way audio-video (AV) equipment is installed.
Figure 1: Typical Video Balun
With recent improvements in copper twisted pair cabling and balun technology, the performance of audio-video over copper twisted pair has improved considerably. Today, there are many balun models supporting a wide range of audio-video formats over Cat5. Some of these environments include composite video, S-Video, RGB, component video, digital audio, analog audio, RF/CATV, DVI, and HDMI. As basic building blocks, these baluns support point-to-point connections over Cat5 and may be used in a wide range of applications including; security video, digital signage, classroom training, boardroom systems and video kiosks.
Originally viewed as a luxury item to support Cat5 cable, today, the balun has become a key element in preserving the investment in a structured cabling system (SCS) and as balun prices decrease, Cat5 is becoming a more attractive alternative to coaxial cable even at short cable lengths under 200ft. This has spurred development of new technology that optimizes analog and digital AV signal transmission over copper twisted pair cable.
As balun technology becomes more accepted in the audio-video environment, the market is moving from a product-centric to a solution-centric industry. More and more products are expected to be introduced that streamline audio-video cabling using copper twisted pair technology. Audio-video equipment that is twisted pair ready will probably be introduced by more vendors on a proprietary basis to capitalize on the advantage of using Cat5 for AV connections. This will precipitate a need for second tier products that support AV transmission over twisted pair. Products such as distance extenders, switchers and distribution amplifiers will probably surface over the next few years to support the many vertical market applications that exist.
MuxLab has been fortunate to be involved in a wide range of applications where balun technology has been applied. As the industry progresses, the key will be whether vendors can successfully build on the basic building block technology and migrate to the next generation products that provide a more complete Cat5 cabling solution. Some of the key areas of activity are described below.
Figure 2: Typical VGA and Keyboard/Mouse Balun Application
Classroom multimedia systems have been dramatically streamlined. By allowing standard Cat5 cabling to be used, balun technology has enabled schools to deploy classroom projector systems more efficiently. Typically a VGA projector is connected to a teacher’s PC. By using balun technology, valuable conduit space is saved and bulky VGA cable is replaced by Cat5.
The proliferation of dazzling new display technologies has led to the development of new applications. Digital signage is one such application. Typically, a server receives digital video content over a network and then outputs the information through a VGA port on the server. A distribution amplifier (DA) may distribute the video content to multiple screens within the premises. Retail stores, airports, hotels and restaurant chains are some of the key users. Balun technology enables these multiple displays to be connected to the video server via Cat5 instead of coaxial AV cable yielding considerable cost savings and preserving the investment in pre-existing cable.
Figure 3: Typical Digital Signage Application
Active, or powered video baluns that amplify and equalize the video signal are capable of supporting extended cable lengths over Cat5 at image resolutions up to 1920 x 1440 pixels, thus placing new applications within distance reach. For example multi-screen video kiosks may be deployed in large stores or public areas more easily where pre-installed Cat5 cable is available.
