Daily authority: 💻 The length of the USB cable is important


Cable from USB A to USB C wrapped around the wrists, connected to the phone with lock icon

Adam Birney / Android Authority

⛄Good morning and welcome to Tuesday’s Daily Authority. It’s currently -8 here in Scotland, but funnily enough that means it’s too cold for snow. I prefer the snow!

How long can USB cables be?

Moga XP5 X Plus Review Micro USB to USB Cable Long

C. Scott Brown / Android Authority

If you’ve ever wondered how long a USB cable can be, now’s the time to find out. Our Zak Khan dived deep to answer the question.

“The maximum length of a USB cable depends on the version of the USB standard it is designed for and whether it is an active or passive cable. Note that the connector style, such as USB-A or USB-C, does not necessarily indicate the version or maximum length. These are the maximum lengths of a passive cable depending on the USB version they are designed for”:

  • USB 1.1: 5 meters (16 feet)
  • USB 2.0: 5 meters (16 feet)
  • USB 3.0: 2-3 meters
  • USB 3.1: 3 meters (9 feet, 10 inches)
  • USB 3.2: 3 meters (9 feet, 10 inches)
  • USB 4: 0.8 meters (31 inches)

Remember that just because a manufacturer claims their cable will work with different USB standards doesn’t necessarily mean it’s true. If a cable is exceptionally cheap but claims to meet high-speed specs, be wary. It is always better to buy from a reputable manufacturer with good reviews.

Why is there a maximum length?

  • In addition to active and passive USB cables, other factors also play a role, such as the thickness of the metal conductors of the cable.
  • If your USB cable also sends HDMI, DisplayPort, Thunderbolt, or other signals, that’s also a problem.
  • Since passive cables do not amplify signals, a longer cable means that the signals transmitted are weaker.
  • That means if your cable is too long (or too long and thin), data loss and slower speeds are likely.
  • A longer cable run can also increase the risk of noise from other devices overwhelming the data signals.
  • Zak explains, “Then there are other, even more technical issues, such as clock jitter, that crop up as speeds and data transfer rates increase.”
  • With active cables – cables that contain circuits that amplify signals – length is a little less of an issue, as the stronger signals can travel farther without degrading.
  • However, you pay more for an active cable, and sometimes they have their own power supply.

Exceeding the maximum cable length

You can extend active cables to a certain level:

  • This is typically 30 meters (98 feet) for USB 2.0
  • For USB 3.0, 3.1. and 3.2, which is about 18 meters (59 feet).
  • Active USB 4 cables are still being introduced, but currently reach about 3 meters (9 feet, 10 inches).
  • Or you can just use a powered USB hub, which plugs into a USB port, and connect your longer cables to the hub.
  • If this still doesn’t work for you, check out some of Zak’s other suggestions in the feature.
  • For advice on USB-C cables, check out our guide to USB-C and our roundup of the best USB-C cables for charging your devices.

Tuesday thing

flush toilet john criminaldi

The next time you use a public restroom, we guarantee you’ll remember this…

  • We know that toilets spray when flushed, sending poop, water and even viruses into the air.
  • Now scientists at the University of Colorado Boulder have made this visible.
  • The team used continuous and pulsed green lasers and cameras to create a thin, vertical sheet of bright green light aimed at the toilet.
  • This sheet lit up to reveal the spray can after a commercial toilet was flushed.
  • You can read more about the team’s results in the paper »Commercial toilets emit energetic and fast-dispersing aerosol plumes,” published in Scientific Reports.
  • Researchers found that the “strong chaotic jet” can reach nearly 1.5 meters in height, with a peak velocity of 2 meters per second within eight seconds of the purge being activated.
  • Larger particles (for the study this was 5 to 10 micrometres) will fall out of the vapor cloud more quickly.
  • Smaller particles can become airborne or settle on bathroom surfaces.
  • Ewww.

Happy Tuesday!

Paula Beaton, editor.