USB 2.0 M-TT Hubs

USB is the most commonly used connection in today’s computer environment. Getting the most out of this connection is a simple matter of planning. By purchasing a hub, most consumers add the convenience of additional ports, but they do not take into account the trade-off: More ports often means reduced speed, especially when mixing high-speed, full-speed and low-speed devices.

It used to be that this loss of performance was simply accepted, as manufacturers couldn’t justify the cost involved with trying to maximize the bandwidth. Times have changed, however; technology pricing has gone done, leaving no excuses for manufacturers not to maximize the throughput speed. There has been a misunderstanding within the USB community that if you wanted to increase the throughput you would simply purchase a USB 2.0 hub. This thinking is flawed, and shows a basic lack of knowledge on the part of many manufacturers. In reality, while the USB 2.0 hubs work fine in conjunction with multiple USB 2.0 devices, the performance of full- and low-speed devices suffered.

When a full- or low-speed device communicates with a USB 2.0 hub, it goes through a TT, a “transaction translator,” chip. In lower-quality, lower-cost designs, there is only one TT chip for the hub. As this single TT chip establishes communication one device at a time, it forces any non-USB 2.0 device to share that chip, which creates a bottleneck in the hub for the 1.1 and 1.0 devices, slowing down their throughput even more. The problem worsens as more devices are attached to the hub. This can reduce transfer speed by as much as 20 percent.

Fortunately, there is a simple solution.

By providing each downstream port with its own TT chip, each device is able to communicate without having to share access, thus removing the bottleneck. This is done through the use of an M-TT, or “multiple-transaction translator,” chip. It keeps the connected devices communicating in the most efficient manner possible. Plus, unlike the single TT environment — in which chip failure prevents the operation of attached full/low-speed (if not all) USB devices — the M-TT minimizes the risk of a catastrophic hub failure.

Keeping your equipment running is one thing: Making sure it runs as efficiently as possible is another. MANHATTAN takes the commitment of quality seriously by offering the best connectivity options that are available to meet your ever-changing needs. And that’s why quality, reliability and efficiency are the trademarks of all MANHATTAN products.

HDMI 1.4 Cable Specifications

HDMI is a changing technology. The demands that have been placed on components and cables have forced changes to be made by both manufacturers and implementers. Since its release in 2003, HDMI has been through several revisions. The latest revision, HDMI 1.4, has brought with it new cable specifications. The division of cable may seem confusing at first, but with a little explanation they are pretty easy to understand. Please note that this is not dealing with the changes to the specifications and features, only to the physical cable itself.

HDMI 1.4 has introduced a few different classifications of cables: Standard HDMI, High-Speed HDMI, Standard HDMI with Ethernet, High-Speed HDMI with Ethernet, Automotive and Micro. HDMI has always been proud of its “single cable connection” standard, and while the addition of these cables may seem to deviate from that format, it really does very little to change the connections themselves. It is just that now there are “grades” of cable.

• Standard HDMI: Supports resolutions up to 1080i/720p with a bandwidth of 4.9 Gbps at 165 MHz.
• High-Speed HDMI: Supports resolutions well beyond 1080p with a bandwidth of 10.2 Gbps at 340 MHz.
• Standard HDMI with Ethernet: Supports resolutions up to 1080i/720p with a bandwidth of 4.9 Gbps at 165 MHz. It also allows support for full-duplex 100 Mbps Ethernet connection.
• High-Speed HDMI with Ethernet: Supports resolutions well beyond 1080p with a bandwidth of 10.2 Gbps at 340 MHz. It also allows support for full-duplex 100 Mbps Ethernet connection.
• Automotive HDMI: This standard HDMI cable is specifically designed for use in the automotive industry. This is a physically different cable because the design must withstand a great deal of punishment from vibration, noise, heat and cold.
• Micro HDMI: This is a change in connection form factor. It does not change the features supported; it is simply a smaller connection package for HDMI. This connector is designed for implementation on small devices.

These different cable classifications have caused a great deal of confusion in the market, and some companies are even taking advantage of this. It’s time, however, to cut through the confusion. Cables are very simple and for the most part remain unchanged in design and connection.

The differences between standard and high-speed cable go back to HDMI versions 1.1, and 1.2. Standard cable is certified to meet the minimum throughput for those standards. Since most cable has been designed to the 1.3 version, this is not a problem and most would qualify as high-speed.

The addition of an Ethernet classification doesn’t change the physical connection, but it does change the wiring structure within the cable. In order to obtain the 10/100 speeds of the Ethernet — and to meet the grade requirements — HDMI cable must now have two of the cables twisted to reduce cross talk.

The Automotive classification simply represents changes in material and the construction for locking the connections. These changes don’t affect the pin outs or the signal, but make the cable tougher in order to withstand the demands inherent in the automotive industry.

Micro classification does not change the cable or signal, either — it only denotes a change in the physical connector used in small devices. Micro HDMI is likely to supplant the mini connection that was introduced earlier.

It seems that most of the confusion has been over terminology. The cables are not different in their connections: All will still use the 19- pin HDMI connection - with micro HDMI cables, of course, in a smaller connection package.
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How much a part of our lives is the Personal Computer?

How much a part of our lives is the Personal Computer? According to a 2007 Wikipedia article, there were a BILLION PC’s in use worldwide and another billion expected by 2014. AMD estimated the population of Internet users to be 1.5 billion as of January 2009. Simply put, everyone has access to a PC and ¼ of the world’s adult population owns one. In the United States, there are more computers in use than there are adults ¹. The computer has become as much a part of our lives as the toaster and the telephone.

Unlike the toaster – well, maybe a little bit like the telephone – the nature of the PC is very personal. The PC is an appliance which the user touches. It takes hours of use to “break in” a new mouse or keyboard to the point where we are comfortable using it, and once we’re comfortable it would take hours to switch back to our old one. This “personalization” doesn’t apply to the PC hardware, but only to the peripherals we touch all day. We don’t buy peripherals based on price or function, we buy them based on design and performance. Sure, if a peripheral is provided to you – say, your company’s computer guy buys you a new keyboard – it may be chosen on price, but if you make the decision yourself you want a product that looks, feels, and performs well. MANHATTAN makes products like this, and we’ve been doing it a long time.

The purpose of this blog is to discuss advances in PC peripheral design and technology. We’ll blog about industry trends and new technologies that directly affect you. Hopefully, we’ll inspire some dialogue from you about what products, trends, technologies, and styles you are interested in.

¹ The United States Census Bureau estimates the population between age 15 and 64 to be 205,794,364 as of July 2009. eTForecasts & Computer Industry Almanac Inc estimates that there were 214,760,000 PC’s sold from 2006-2008.