USB extension cable

[EliteXen]

Anyone know a good 30-50 ft USB extension cable I'm trying to run a keyboard to another room.

Don't suggest wireless, I already have three wireless keyboards hooked up to this computer. I use a Logitech MX 5000 when I'm sitting at my desk and the Belkin MediaPilot when I'm in the other room, but I want to move the Belkin's docking station to the other room so I don't have keep running back and forth to charge it.

 

[rise]

http://www.ebusinesscables.com/cable_extenders.htm

google returned a surprisingly large # of results. thats just one.

 

[EliteXen]

Originally posted by: rise4310
http://www.ebusinesscables.com/cable_extenders.htm

google returned a surprisingly large # of results. thats just one.

Google had a lot of cables but not very many as long as 50ft. Many of the longer ones also said they were active or passive extension cables. All I've ever used were passive cables so I wonder how the active would affect the performance of the keyboard.
That site you linked to only has 1 type that is as long as 50ft and it converts the USB to RJ45 then back to USB on the other end. I've never used something like that and paying $100 bucks for a cable is a bit extreme.

 

[Tu13erhead]

USB Specifications limit the cable length to 5 meters (about 16 feet).

See: Link

2. I want to build a cable longer than 5 meters, why won't this work?
A: Even if you violated the spec, it literally wouldn't get you very far. Assuming worst-case delay times, a full speed device at the bottom of 5 hubs and cables has a timeout margin of 280ps. Reducing this margin to 0ps would only give you an extra 5cm, which is hardly worth the trouble.

3. What about using USB signal repeaters to make a cable longer than 5 meters?
A: Don't bother. The best solution is self-powered hub with a fixed 10m cable that had a one-port bus powered hub in the middle. The maximum range will still have to deal with the timeout, so any out of spec tweaking of the terminations between the two hubs and the timing budget still won't yield more than 5cm of extra distance. A better solution is described in the following question.

4. I really need to put a USB device more than 30 meters away from my PC. What should I do?
A: Build a USB bridge that acts as a USB device on one side and has a USB host controller at the other end. Use a long-haul signaling protocol like Ethernet or RS-485 in the middle. Using cables or short-haul fiber, you can get ranges upwards of a kilometer, though there's no reason why the long-haul link in the middle of the bridge couldn't be a pair of radio transceivers or satellite modems.
Embedded host solutions capable of doing this already exist. Also, two PCs connected via USB Ethernet adapters are essentially a slave/slave version of this master/slave bridge.

That's essentially what the above adapter is.

 

[EliteXen]

Thanks for the info.