USB cord length

[Britjoe]

Anyone know if there's a working restriction on a length for USB 2 cord im running A 20FT cord, I have a touch screen on my media center screen as I use as the control for Media, Video, music and my big screen, any how it seems to work for about 15mins and then goes a little flakey and stops workin. the only way to rectify it is pull out the USB to the back of the monitor and plug it back in,

 

[kado897]

According to Wikipedia it is 5 meters. USB - Wikipedia, the free encyclopedia

 

[marsmimar]

And verified by usb.org

USB.org - FAQ: Cables, Connectors, and Networking

 

[ltmcmullen]

Anyone know if there's a working restriction on a length for USB 2 cord im running A 20FT cord, I have a touch screen on my media center screen as I use as the control for Media, Video, music and my big screen, any how it seems to work for about 15mins and then goes a little flakey and stops workin. the only way to rectify it is pull out the USB to the back of the monitor and plug it back in,

Hi, we just went over this topic not too long ago in my Computer Tech. class. I will give you a breakdown on what the instructor gave us (these are max lengths):

Serial @ 9600 bps................................20 feet
EPP/ECP Parallel...................................20 feet (6 meters)

USB 1.1 Full Speed...............................10 feet (3 meters)
USB 2.0 High Speed..............................16.4 feet (5 meters)

1394a (Firewire400)..............................14.8 feet (4.5 meters)
1394b (Firewire800)..............................328 feet!!! (100 meters) *Optical :shock:

I hope this helps you and isnt t.m.i.

 

[ltmcmullen]

Oh and by the way, I have found that those USB jacks on the monitors are not all what they are jacked up to be. Well, at least the one I have used (sorry Dell!)

 

[kado897]

You can also get active repeaters which can extend another 5 meters. I don't know whether you can daisy-chain those to get longer lengths than 10 meters.

 

[marsmimar]

From my previous post and link:

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.

 

[kado897]

Ah that makes sense. I missed that. I guess an active repeater is just a hub with one input and one output.

 

[ltmcmullen]

From my previous post and link:

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.

I know I'm still learning all this stuff... but... would it not be better to just go IEEE 1394? That way you can dismiss the distance issues and have the capability to connect up to 63 peripherals?

 

[marsmimar]

I know I'm still learning all this stuff... but... would it not be better to just go IEEE 1394? That way you can dismiss the distance issues and have the capability to connect up to 63 peripherals?

Sure. But Op specifically asked about length restrictions for a USB 2 cord. And not every machine, especially laptops, have FireWire connectivity. (Like my ancient Dell Inspiron 1200 running Ubuntu. )