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.