usbview says that the hub on one of the 2408's we have here is self-powered, so it should be able to supply the full 500mA on each of its ports. Whether that 500mA is enough to power an external HDD, I don't know - some drives are fine with that, and some aren't.
Actually, to be pedantic, usbview says that the 2408 is a nested pair of hubs, both of which are self-powered. There's a two-port hub at the top level, one of whose ports is connected to another 4-port hub. That 4-port hub has the card reader plus 3 of the external ports hanging off it.
It's a bit of an odd arrangement - I would perhaps have expected a 5-port hub with one internal port stolen by the card reader, so that if the monitor is plugged in as the last in the longest chain of hubs allowed by the USB spec, the user wouldn't get a surprise when only one of the external ports worked (and not the other three ports nor the card reader), but that's just me.
wow thats a very detailed answer. just got myself a copy of usbview and i see the cascading hub structure. very funny design by Dell.
whats the opposite of self-powered? and whats the difference? so that means the usb hub steals some power from the power from the monitor to power itself is that right?
thanks again for the detailed answer. will wait if there is an official answer from dell, if not will mark your post as solution.
random_gibberis
2 Posts
0
October 7th, 2008 01:00
usbview says that the hub on one of the 2408's we have here is self-powered, so it should be able to supply the full 500mA on each of its ports. Whether that 500mA is enough to power an external HDD, I don't know - some drives are fine with that, and some aren't.
Actually, to be pedantic, usbview says that the 2408 is a nested pair of hubs, both of which are self-powered. There's a two-port hub at the top level, one of whose ports is connected to another 4-port hub. That 4-port hub has the card reader plus 3 of the external ports hanging off it.
It's a bit of an odd arrangement - I would perhaps have expected a 5-port hub with one internal port stolen by the card reader, so that if the monitor is plugged in as the last in the longest chain of hubs allowed by the USB spec, the user wouldn't get a surprise when only one of the external ports worked (and not the other three ports nor the card reader), but that's just me.
CrymsonArray
133 Posts
0
October 8th, 2008 14:00
wow thats a very detailed answer. just got myself a copy of usbview and i see the cascading hub structure. very funny design by Dell.
whats the opposite of self-powered? and whats the difference? so that means the usb hub steals some power from the power from the monitor to power itself is that right?
thanks again for the detailed answer. will wait if there is an official answer from dell, if not will mark your post as solution.