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Long USB Cable

  • 18-07-2006 7:38am
    #1
    jamieh
    Registered Users, Registered Users 2 Posts: 2,073 ✭✭✭


    Hey all,

    Does anyone know what's the longest USB cable you can use before performance starts to drop?

    I'm backing up my server onto an external hdd but I want to put the hdd in a fire-proof case which is about 30 feet away from the server.

    Is it possible to get a cable that long?


Comments

  • #2
    Ponster
    Moderators, Recreation & Hobbies Moderators Posts: 10,912 Mod ✭✭✭✭Ponster


    From USB.org :

    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).


    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


    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.


    I think that this means that longer than 16 feet and you'll get a performance drop but I can't find any figures to show exactly what kind of drop. Even if it was 50% would it mean that it was twice as slow yet would do the job just as well?


  • #3
    Random
    Closed Accounts Posts: 19,080 ✭✭✭✭Random


    You can also get USB boosters for every 5 metres.


  • #4
    jor el
    Closed Accounts Posts: 16,713 ✭✭✭✭jor el


    I assume those hubs or boosters would need to be powered, in which case you'll also need plenty of electrical sockets along the length of that 30 ft. Is moving the server and case closer together an option at all?

    Could you use a network storage device, such as this, instead of the USB hard disk and use a long ethernet cable (up to 100m allowed) to connect it to the server?


  • #5
    DemonOfTheFall
    Closed Accounts Posts: 2,279 ✭✭✭DemonOfTheFall


    I wouldnt risk rigging up a longer cable than spec. I assume data corruption and other nasty stuff would be possible ?


  • #6
    paddyp
    Closed Accounts Posts: 1,927 ✭✭✭paddyp


    http://www.lindy.com/uk/productfolder/04/42801/index.php

    Thats USB 1.0 though. NAS as suggsted is a much better idea.

    Or you could try:
    http://www.komplett.ie/k/ki.asp?sku=317554

    http://www.komplett.ie/k/ki.asp?sku=307213


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  • #7
    Capt'n Midnight
    Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 93,565 Mod ✭✭✭✭Capt'n Midnight


    for cheap + long but slow

    in the €2 shops you can get 1.1 USB hubs, extent the cables to 10 - 20 m and daisy chain 5 of them in a row. Best to have thicker wire for the 5V too.


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