[Solved] What is the maximum cable length of a USB cable?

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Icon ask Sir ApfelotQuestion: I have an external hard drive that I would like to put away from my Mac. In stores you can find USB cables in lengths of 0,9 m, 1 m, 1,5 m, 2 m, 3 m and even 5 m. My question is: What is the maximum length of a USB cable?

Answer: The answer was not that easy, because there are lively discussions on this topic in various forums. I find it striking that normal USB cables (regardless of whether USB 2 or USB 3) are only available in lengths of up to 5 meters. According to Wikipedia, this is also the maximum length of a USB cable before it should end in a USB device or a USB hub. Wikipedia says under USB hubs / general this excerpt: “The maximum distance between two USB-connected devices is 5 m because of the limitation of 30 m per USB cable – six cables, each five meters long and five hubs in between.” That means you should definitely choose a cable no longer than 5 meters if you don't want to take the risk that the data transfer between the computer and the USB device (like a [USB hard drive->external-usb-hard-drive]) should not be disturbed, very slow or riddled with data errors.

Update 10-2016: I have a new post on the topic here”USB extension” written in case you are interested in the topic. Solutions up to 50 or 60 m transmission path are also presented there.

USB extension with 10 meters and more

There are still exceptions. For example, you can do one USB Hub after the 5 meters of cable install and then extend the connection by another 5 meters. According to Wikipedia, the game can be played with up to 6 cables and 5 hubs, so that in the end you get to a proud 30 meters.

The other solution is [active USB-2 cable-> USB-2 extension], which have a built-in repeater for signal amplification. These cables then usually have a USB Type-A connection with a USB plug on one end and a USB socket on the other end of the cable, so that the actual USB cable can be plugged into this USB extension. With the built-in repeater, cable lengths of 10 m, 15 m and even 20 m are possible. However, if external hard drives are to be connected after this length, you first have to connect an active USB hub with its own power supply to the end and then plug in the external hard drive.

USB-3 cable only up to a maximum length of 5 m

A pair of active USB 3 cable However, it is only found up to 5 m. Larger distances are probably not technically feasible there because of the high data rate.

Repeater USB 3 extension cable with 5 m
This type A extension cable (USB-A plug to USB-A socket) also supports USB 3 and has active signal amplification, but without an extra power supply unit.

A corresponding active USB 3 hub that does its job well on the Mac is, for example, that of Anker. It also understands USB 2 and can also supply USB 3 devices with data in parallel. It is important that the USB 3 devices are not slowed down if you also plug in a USB 2 device, because this is the case with some hubs.

Anker USB 3 Hub - active with power supply
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Anker USB 3 Hub - active with power supply
This active USB 3 hub from Anker offers 4 ports and a 5V port with 2.1 amperes to quickly charge devices such as an iPad. Thanks to the external power supply that is supplied, you can also connect several external hard drives that do not have their own power supply.

Longer cables of 10 m and more are only available up to the USB-2 standard

USB-2 extension with 5 m
This DELOCK USB extension cable supports USB 2 and has a cable length of 5 m.
USB-2 extension with 10 m
This DELOCK USB extension cable supports USB 2 and has a cable length of 10 m.
USB-2 extension with 15 m
This DELOCK USB extension cable supports USB 2 and has a cable length of 15 m.
USB-2 extension with 20 m
This DELOCK USB extension cable supports USB 2 and has a cable length of 20 m.

If you only work with USB 2 cables, you of course only need an active USB 2 hub. Here you can recommend Belkin’s:

USB 2 hub with 7 ports (active)
This active USB 2 hub offers 7 ports that can be used for all kinds of USB devices. Thanks to the power supply, external hard drives also work with the hub without their own power source.


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2 comments on "[Solved] What is the maximum cable length of a USB cable?"

  1. Nice article. Lived experience in the recording studio. If longer distances have to be covered, then a USB hub is unfortunately another source of error. Good USB amplifier cables solve the problem, although there are also big differences here. Without these amplifiers, critical applications with a cable length of 5 meters or more can lead to massive errors.

    1. Hi Andreas! Thanks for your information. Which USB amplifiers do you use? That would be a nice addition to the article. Thank you! LG, Jens

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