usb hubs and "piggy-backing"

[danIT]

Our PE department have a number of electronic dance mats which all need to be linked to a laptop via a usb hub. They have around 30 mats so we need a usb hub with 30 ports.

 

We dont seem to be able to find a hub with 30 ports, firstly does anyone know if a 30 port hub is possible/available. Secondly could we buy say 4 8 port hubs and piggy back them to add support for more connections?

[Geoff]

You should only connect 5 tiers of USB hubs together. A tier is defined by the number of hubs a device's signal must pass through before it reaches the host.

 

For example, using a 4-port USB hub, you could connect a theoretical maximum of 341 hubs in five tiers. This would leave you with 1024 ports to connect USB devices.

 

However Windows XP has a hardcoded limitation of 127 USB devices. If you want more, you'll need to use a real OS like Linux or Mac OSX.

[_Bob_]

In theory you can daisy-chain up 128 USB devices IIRC. In practice I would make sure you get powered hubs for something like this as you are likely to run into voltage problems otherwise.

 

[_Bob_]

Damn Geoff can create those Linux advertisements quicker than a mere mortal can compose a reply!

[indie]

As Geoff said, no more than 5 tiers, just buy a load of POWERED USB hubs and it *should* work.