What 10m USB extension cable can I use for a USB display?

12
2013-08
  • Lekensteyn

    The Lenovo LT1421 is a 14 inch monitor that can be connected using a USB B mini to USB A cable. It is shipped with a 1.8 meter cable which is too short for my purpose.

    USB is limited to 5 meter, but there exist "active" USB cables that boost the signal. Are such cables sufficient for DisplayLink devices such as this Lenovo monitor or do they only work for things like keyboards? Should I consider other cables or devices instead?

    • Answers
  • Lekensteyn

    Plugable claims that their 10M USB extension cable works with DisplayLink USB displays (emphasize mine):

    Connect USB printers, scanners, displays, keyboards, etc from across the room with this 10 meter / 32 foot USB 2.0 extension cable. Active repeater (bus powered single port hub) and a premium shielded cable enables this unit to have 2x the length of a standard USB cable. The tradeoff, however, is devices with precise timing requirements (isoch devices, usually USB video cameras) will not work with this cable. Will work with nearly all other devices: devices such as printers, scanners, DisplayLink USB displays, keyboards, mice, and most miscellaneous USB devices.

    I am unable to verify their claim, nor do I know whether it this cable can be connected with the existing USB-A/USB-B mini connector.


    • Related Question

    Maximum length of a USB Cable?
  • Click Ok

    I want to use a very long USB cable to place a webcam in a different room. The maximum length that I found was five meters.

    1. What is the maximum length of a USB cable?

    2. What is the maximum length achievable when using USB extension cables?


    • Related Answers
  • quack quixote

    5 meters is the maximum USB cable. You can get further by connecting USB hubs serially (maximum of 5 hubs chained this way). You can't just use USB extension cables due to timing issues.

    From the USB FAQ:

    Q1: How long of a cable can I use to connect my device?
    A1: In practice, the USB specification limits the length of a cable between full speed devices to 5 meters (a little under 16 feet 5 inches). For a low speed device the limit is 3 meters (9 feet 10 inches).

    Q2: Why can't I use a cable longer than 3 or 5m?
    A2: USB's electrical design doesn't allow it. When USB was designed, a decision was made to handle the propagation of electromagnetic fields on USB data lines in a way that limited the maximum length of a USB cable to something in the range of 4m. This method has a number of advantages and, since USB is intended for a desktop environment, the range limitations were deemed acceptable. If you're familiar with transmission line theory and want more detail on this topic, take a look at the USB signals section of the developers FAQ.

    Q3: How far away from a PC can I put a USB device?
    A3: With the maximum of 5 hubs connected with 5m cables and a 5m cable going to your full speed device, this will give you 30m of cable (see section 7.1.19 for details). With a low speed device, you will be able to get a range up to 27m, depending on how long the device's cable is. With a straightforward cable route, you will probably be able to reach out 25m or so from the PC.

    Q4: I need to put a USB device X distance from my PC. What do I do?
    A4: If X is less than 25m or so (see previous question), buy a bunch of hubs and connect them serially with 5m cables. If you need to go farther than that, put another PC, or maybe a laptop, out where you need the device to be and network it with the first PC using something that's intended to be a long-range connection, such as Ethernet or RS-485. If you need to use nothing but USB, consider using USB based Ethernet adapters to hook the PCs together.

  • Area 51

    if you want to go beyond 5 meters, use a booster.