USB Extenders vs. Passive Cables vs. Active Cables
Due to the limitation of the maximum length of the USB cable, we need to find a way to extend USB signal when the distance between devices is too far away. USB extenders, passive USB cables, and active USB cables all allow us to reach much longer distances without signal loss.
What are they? And how to choose them? This blog will give you the answer.
Max. Data Transfer Rate & Cable Length Limits:
| USB Specification | Max. Data Transfer Rate | Recommended Cable Length |
| USB 1.0 (Full Speed) | 12 Mb/s | 3 m (9 ft.) |
| USB 2.0 (High Speed) | 480 Mb/s | 5 m (16 ft.) |
| USB 3.2 Gen 1 | 5 Gb/s | 2-3 m (6-9 ft.) |
| USB 3.2 Gen 2 | 10 Gb/s | 3 m (9 ft.) |
| USB 3.2 Gen 2×2 (USB-C only) | 20 Gb/s | 3 m (9 ft.) |
| USB4 (USB-C only) | 40 Gb/s | 0.8 m (31 ins) |
The USB standard was first designed to link desktop computers to peripherals including storage devices, mouse, printers, and keyboards. Devices were often close together. Today’s USB cables are used for a variety of purposes outside of the desktop.
For instance, connecting a laptop’s USB-C connection to a wall-mounted display 30 feet distant or a camera in a hallway to a computer in an office is commonplace. With certain cables and extenders, USB connections can now be extended.
Let’s examine USB cable length restrictions in more detail and discover ways to prolong a USB connection without reducing signal strength.
Why Are USB Cables Limited in Length?
A USB host waits for a response before transmitting the next “packet” of data to a device connected by a USB cable. It sends the packet again if there is no answer.
The amount of time the USB host has to transmit and receive data packets decreases as the data transfer rate increases. High data transfer rates often demand a shorter connection since the further the signal must travel, the more probable it is to experience an error known as a “late collision.”
The conductivity of copper itself also places a limit on the maximum length of USB cables. A signal loses some intensity as it moves across a copper wire. Attenuation, also known as signal loss, is quantified in decibels (dB) per foot or meter. The signal loss increases with distance until it reaches the point where the receiver is unable to recognize or comprehend the signal. By using a wider gauge, well-insulated USB cable, signal loss can be minimized.
Noise is also a problem with copper cabling. For instance, excessively close cable runs to light fixtures or power wires may add noise to the signal, which lowers the signal’s quality rather than its strength. Strategies for reducing the impacts of signal distortion are part of communication protocols like USB.
Extend USB Signal with Passive Cables
A simple cable arrangement with a USB connector on each end is known as a passive cable. Passive cables are subject to the attenuation and noise issues mentioned above since there is no attempt to amplify or regenerate the signal.
However, passive cables that are typically designed for more than the maximum distance recommended will have thicker cables and better shielding, which can help USB signals extend a bit further than “standard” cables.
Extend USB Signal with Active Cables
Data may be carried across greater distances with active cables because they have circuitry that regenerates the signal, typically at the receiving end. Although longer connections may have the option of an additional AC adapter or USB-A connector to guarantee the signal booster has enough power, active cables usually are “bus powered.” As long as each transceiver in the chain has access to power, active cables can be daisy-chained.
Extend USB Signal with USB Extenders
In reality, a USB over Cat5 or Cat6 extender is a single port hub. The USB signal is converted into Ethernet, transmitted through an ordinary category cable, and then converted back to USB at the other end.
If you are looking for a cost-effective USB extender, AV Access U2EX50 is the one you can’t miss. It can connect 4 USB devices(such as a keyboard, mouse, and webcam) and extend the USB 2.0 signal up to 60 meters/196 feet.
More Resources
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Source: https://www.avaccess.com/blogs/guides/usb-extenders-vs-passive-cables-vs-active-cables/
