USB Powered Speakers

Warren Block wblock at wonkity.com
Fri Apr 9 11:38:51 UTC 2010


On Fri, 9 Apr 2010, perryh at pluto.rain.com wrote:

> Programmer In Training <pit at joseph-a-nagy-jr.us> wrote:
>
>> ... they are only attached for power purposes ...
>
>> Input power: DC 5V 500mA
>
> Any chance these speakers need a USB 2.0 port, and all the ports
> on your FreeBSD box are 1.x?  I don't remember the USB power spec
> offhand, but 2.5W may exceed what a USB 1.x port can supply --
> a limit that applies regardless of the system's overall power
> provisioning.

500 mA is 5 unit loads for USB 2.0, or powered hub territory.  The 
device has to request that high power mode, and the system can say no 
and disable the port.  That should show in /var/log/messages.

-Warren Block * Rapid City, South Dakota USA


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