USB 2.0 cable length ?

[Orc General]

Does anyone know the limitations of USB 2.0 cable length? Up to how long
can you hook a webcam to such a cable and still get a picture out of it?
I am looking to use one or two USB webcam as a cheap security camera, ie
string it across the apartment with a long USB cable. But I am not sure if
the long cable will still provide power to the webcam. Anyone know?

 

[Tim Wescott]

Orc General wrote:

Does anyone know the limitations of USB 2.0 cable length? Up to how long
can you hook a webcam to such a cable and still get a picture out of it?
I am looking to use one or two USB webcam as a cheap security camera, ie
string it across the apartment with a long USB cable. But I am not sure if
the long cable will still provide power to the webcam. Anyone know?


4 meters, IIRC. Part of the IEEE-1394 spec encompasses cheap optical

fiber that give you longer cable runs but you'd need bridges to go from
copper to fiber and back -- and I don't know if such things exist in
consumer space.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Mark VB]

Orc General wrote:

Does anyone know the limitations of USB 2.0 cable length? Up to how long
can you hook a webcam to such a cable and still get a picture out of it?
I am looking to use one or two USB webcam as a cheap security camera, ie
string it across the apartment with a long USB cable. But I am not sure if
the long cable will still provide power to the webcam. Anyone know?

The maximum allowable cable length is determined by signal pair
attenuation and propagation delay. According the USB-standard, the max.
delay for a full-speed cable must not exceed 26ns. So, theoretically,
the max. cable length is somewhere between 5 and 5.2 meters.


HTH,
Mark Van Borm

 

[Joel Kolstad]

"Mark VB" <mark@vb.invalid> wrote in message
news:NK6Pe.177710$YW4.9938052@phobos.telenet-ops.be...

According the USB-standard, the max.
delay for a full-speed cable must not exceed 26ns. So, theoretically,
the max. cable length is somewhere between 5 and 5.2 meters.

I'm just waiting for someone to come out with their "extra long" 6-7 meter
cable that uses a supported air dielectric so that they can get the relative
velocity up to, say, 90%

 

[Wouter van Ooijen (www.vo]

Does anyone know the limitations of USB 2.0 cable length? Up to how long
can you hook a webcam to such a cable and still get a picture out of it?

You could consider those active extension cables (more or less a
cablke with a one-port hub at the far end).


Wouter van Ooijen

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