como funcionar, funciona, pero para usar al mismo tiempo un disco duro y otros dispositivos usb siempre se recomienda un hub usb alimentado externamente, para no sobrecargar el consumo por el puerto usb del deco, y evitar posibles averias por sobre carga.
un puerto usb suministra 500 mA, y si conectamos varios dispositivos que sumen mas, o lo calientan ó no funcionan bien, por falta de voltaje, por eso se necesita un hub alimentado con fuente de alimentación propia, para que le suministre a cada puerto del hub los 500 mA de consumo.
Definitions
USB Host = The computer, only one host per USB system.
USB Device = A
hub or a
Function.
Power usage:
Bus-powered hubs: Draw Max 100 mA at power up and 500 mA normally.
Self-powered hubs: Draw Max 100 mA, must supply 500 mA to each port.
Low power, bus-powered functions: Draw Max 100 mA.
High power, bus-powered functions: Self-powered hubs: Draw Max 100 mA, must supply 500 mA to each port.
Self-powered functions: Draw Max 100 mA.
Suspended device: Max 0.5 mA
Voltage
- Supplied voltage by a host or a powered hub ports is between 4.75 V and 5.25 V.
- Maximum voltage drop for bus-powered hubs is 0.35 V from it's host or hub to the hubs output port.
- All hubs and functions must be able to send configuration data at 4.4 V, but only low-power functions need to be working at this voltage.
- Normal operational voltage for functions is minimum 4.75 V.
Shielding
Shield should only be connected to Ground at the host. No device should connect Shield to Ground.
