USB cables - transport data reliably

What is a USB cable?

USB (Universal Serial Bus) is a serial bus system used to connect external devices to a computer. Introduced in 1996, it had been used mainly on home and personal computers. In the meantime, there is more and more use in industrial applications, such as in vision cameras. Since their introduction, the variety of interface types, which were usually provided with different connectors, were replaced. USB has thus developed as a standard, which has its advantage in that the devices can be connected during operation (hot plugging) and the connected devices are automatically detected.
 
With the introduction of USB 1.0 in the year 1996 the data rate was still pretty slow with max. 12 Mbps. In 2000, USB 2.0 was specified at a data rate of 480 Mbps. This is still the most widely used version today. The USB 3.1 Gen 2 introduced in 2014 already had a maximum transfer rate of 10 Gbps, which was increased to 20 Gbps with the USB 3.2 specified in 2017.
 

USB cable application areas

Transmission lengths

The topic of the maximum transmission length of USB cables is often underestimated. In general, caution should be exercised, as the maximum cable length can vary greatly depending on the type of cable. A cable for fixed installation always has a lower dampening than flexible cables, which is designed for permanent movements. As a result, the transmission length is lower than with a cable for fixed installation.
 
Depending on the cable range, chainflex bus cables are mechanically designed for travel distances of up to 400m or more, but the data rate of the bus system decreases with increasing cable lengths. With USB 2.0, a maximum cable length of 5m without repeater is possible according to specification. With USB 3.0 it is only 3m. Especially with USB devices that require the full data transfer rate, such as HD cameras, the cable length can be a problem. Due to the attenuation of the cable in combination with the cable length, the transmission speed drops and transmission errors can occur. With highly flexible USB cables for the energy chain, however, our experience shows that one cable length can possibly be shorter. Depending on the required transmission speed, up to 2.50m may only be possible for a moving USB 3.0 cable. However, this length may vary further up and down depending on the environmental conditions and application requirements.