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8 Critical Considerations For Finding the Best USB Extension Solution

Before we get into the considerations for finding the best USB extension solution, it may be helpful to review a few key points about the standard and common methods available. While this is not intended to be an exhaustive list, it should provide a high-level understanding and help you make a more informed decision and options available

USB Background

Few would argue against the usefulness that USB as a technology, has earned over the last several decades for its plug-and-play simplicity and “just works” robustness in connecting our keyboards, video cameras, and mice.  As technology has improved, so has the demand placed upon this once simple connector. The standards body that develops the USB specifications has done a great job of continuing to expand and push the limits beyond what many thought was possible; making it ever more useful for handling nearly everything our PCs, MACs, and mobile supercomputer users have thrown at it in the form of audio, video, data, control, and power for our devices. So much so, that few of us ever give the trusty connection a second thought. However as it’s evolved, its capabilities are being put to the test from a growing list of more sophisticated technology applications, which can contribute to issues.

Lately, if you’ve noticed the cables that come with your devices seem to be shrinking, you’re not alone. The standards body has defined a strict distance limitation in order to accommodate affects of the growing complexities related to improving electrical and communications performance. So, what you are noticing is real since the maximum cable length is in fact, inversely proportional to its max speed.

According to the USB-IF Standards, the maximum standard cable lengths are defined as shown below:

USB-IF Standards Bandwidth and Cable Length

 

Unfortunately this is not good news for all of us who’ve been frustrated of having to huddle ever closer to a charging station, or are sore from pounding our wireless keyboards and mice into the table to wake up. Thankfully, there are other options, albeit with their own tradeoffs to consider.

Enter USB extension solutions, offering us all some much needed breathing room (especially these days). These active hubs and extension cables are generally reliable, but to be clear, installers should understand and realize some of the trade-offs that may affect individual applications. For example, unlike HDMI, USB requires bi-directional communication, with data flow strictly controlled to minimize latency for applications like video and audio streaming.

So to help you understand your options, here are the most common generally accepted methods available for extending USB.

Active Cable

Active Copper cables offer a way to, but require regular amplification throughout the cable, which add bulk and limit its use in some applications. For example, because of the “pregnant snake” look caused by power amplifiers, its not as easy to hide and because of this extra bulk can prevent installation in a ceiling floor, or wall, especially for conduit applications. Also generally not accepted by most building codes to have an active device inside of the wall or ceiling.

Active USB Cable
USB Active Cable (Copper)

Active Optical Cable

USB Active Optical Cables (AOC), also known as Optical Isolated Active Cable (OIAC), use an electrical to optical conversion over a hybrid fiber and thin copper wire combined in a single cable, to enable much longer distances,  generally up to 30 or 50 meters, depending on the application.  The thinner construction of this cable also makes it more suitable for use in conduit such as in-wall or in-ceiling installations. However you may need to check your local building codes or make sure your selected cable jacket is plenum rated. One limitation with AOC is the it has limited capacity for power so may not work or limit use on devices that require that juice.  For instance, Some devices use USB 3 and USB 2 in certain circumstances that may require a different cable solution or extension solution to be fully operational. Therefore it is a good idea to verify the specifications of the the devices you are trying to connect to make sure it will work, especially before you get in the field where time and material mistakes may be more costly. Costs of AOC are generally slightly more expensive than copper, but can offer distinct advantages as well.

Active Optical Cable (Hybrid)
Active Optical Cable (30M)

Dedicated Devices and Hubs

The other common method for extending USB is a dedicated piece of hardware to modulate and demodulate the signal, but also to process, convert and split, or repeat the signal to additional ports. This can offer some additional benefits like even greater distances (up to more than 2 miles in some cases) and greater more conversion options.  This however, comes at a higher price than cable alone.

The primary methods for extending USB via conversion are via SDVoE, HDBaseT™, AVoverIP, etc. Of these, HDBaseT is arguably the most common of these solutions on the market today, capable of converting HD video, audio, power, Ethernet, USB 2.0 and control signal over Category based cabling.  The HDBaseT standard has been around since 2010 and offers a great solution for reliably transmitting AV with near zero latency over distances up to 100meters. However, its limitation is it is only capable of supporting USB 2.0 bandwidth up to 280Mbps in the HDBaseT 2.0 spec and only 350Mbps in the latest HDBaseT 3.0 spec due to the headroom required for the HDBaseT packets. So what this means to USB is uncompressed video is capped at a low resolution (480p or lower) video stream. To check your application, to see if your device can reliably function, you can calculate the video bandwidth as follows:

  • Data rate = color depth × vertical resolution × horizontal resolution × refresh frequency
  • Standard HD (720p @ 30 fps) and 8-bit color-depth  = 8 × 1280 x 720 × 30 = 221 Mbps, ok but going to Full HD will be a problem
  • Full HD (1080p @ 30fps) and 8-bit color-depth = 8 x 1920 x 1080 x 30 = 442Mbps. Therefore HDbaseT is not as well suited for delivering uncompressed HD USB video and is better suited as an HDMI extension solution that are converted within the native HDBaseT output device.

ClariFi USB Extension Systems

The ClariFi Active Extension solutions use a purpose-built solution made for USB to solve the performance and reliability unmatched by other methods. It also is capable of distances up to 100 meters (328 ft.) over a standard CAT cable, and uses a patented technology from Icron™ called Extreme USB™ that is capable of supporting up to 5Gbps bandwidth of USB 3.2 Gen 1, while also concurrently supporting USB 2 and 1.1. This makes it uniquely capable of supporting a much broader array of uncompressed Full HD video applications as well as supporting additional USB applications like peripherals (Audio, control, etc.) that may run at the lower bandwidth. The USB 3ES PRO uses unique technology making it the only solution available on the market capable of reliably supporting USB 3 Isochronous communications over such distances, to guarantee bandwidth critical for some multi-function HD video and audio conferencing platforms like dedicated Google Meet™ hardware or Zoom™ Room hardware. This solution also is capable of multi-port output, ideal for Bring Your Own Device (BYOD) and up to 1.5A of power for those remote devices, unlike AOC cable.

So now that we've covered the technologies available, before selecting which USB extension method is best, the following must be considered for your individual application:

1)     Peripheral type:

  • What type of peripheral devices are you trying to connect and what is the USB port used for? It may be helpful to review the specs of your device here.
  • Keyboard and mice will likely just use use USB 1.1 or USB 2.0, but may not work over purpose built USB 3 AOC that can only support USB 3 devices.
  • USB 3 video devices may or may not also support USB 2 video fallback or may use audio over USB 2, for a mic.
  • If a conferencing system, like dedicated Google Meet™ hardware or Zoom™ Room hardware,  it may also rely on isochronous transmission for specific applications.  

2)     Host device type: 

  • Is the host device a dedicated PC/MAC to the room or is one available that can do the processing?
  • Where is it to be located….Is it local or served from a control room?
  • Is it used in a conference room or place where other devices will need to plug-and -play, such as a Bring Your Own Device (BYOD) conference room ?

3)     Number of devices and communication or transaction types

  • Are you connecting more than 1 device and what types of communication is required?
  • Audio, video, control (e.g. sensors, touch controls, PTZ commands), data transfer, power, etc. can all have different transaction types.

4)     Power requirements

  • Is my device powered via the USB port or does it have ancillary inputs? For example, a USB 3 AOC can be used for a Logitech Rally camera, but requires the use of power splitter to support the power requirements for the device to work.
  • If port powered, what voltage is needed?
  • Since AOC cable has a limited power capacity(typically not more than 5V), it may require some configuration changes to work.  

5)     Video requirements

  • What is the intended image quality? If you have invested in a camera and display capable of full HD, you want your infrastructure to support it, now and in the not too distant future.
  • Does the device souce (i.e., camera0 provide uncompressed USB 3.0 or does it negotiate down to USB 2.0, and or compress over USB 2.0
  • Does it use Bulk or Isochronous for Video transaction

6)     Audio requirements

  • Is it a standalone audio device or is it from a multi-function device (such as an all-in-one video conference + mic or speaker).If so, is it over USB 2.0?
  • Does the device use UAC for USB transmission

7)     Installation considerations

  • Will cable be crossing a table or going between rooms?  
  • Does the cable need to be hidden for either safety or aesthetics, like in a wall or plenum ceiling?

8)     Connector type

  • Is the port on the peripheral a USB 2 or a USB 3 port (blue or indicated by SS for SuperSpeed)
  • Is it a USB A, B, C, and what if any power delivery is used (often indicated with a "PD" or lightning bolt symbol)
  • Make sure the devices are compatible and minimize number of intermediary connections, as these increase the number of potential failure points.

So, if possible spend a little time to dig a little into your devices specs.  When you still are unsure, any good supplier will recommend you test solutions to validate functionality.  ClariFi offers a 30-day trial for all of its products to enable you to test and ensure it works for your individual application before deployment. ClariFi products are all rigorously tested with USB compliant guidelines and real-life applications, to ensure our products provide a clear difference in usability and reliability.  See our compatibility matrix for the latest interoperability validation.

To learn more about our products:

USB AOC Cables

USB Extension Systems

USB Extension System Compatibility Matrix

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