|You can find out how much current a USB device draws in |
Device Manager - USB Controllers - Root Hub - Power tab. However, I'm not sure whether that is a actual reading or an an un-changing static rating specified in specs Windows has been supplied with for the device.
A USB 2.0 controller is backward compatible with USB 1.1 specs.
Device Manager shows both it's USB 2.0 support (Enhanced or similar Host Controller) and it's USB 1.1 support (Enhanced or similar NOT in the Host Controller line).
When you look at Root Hub - Power tab....
Root Hubs for the USB 1.1 support usually have two ports per Root Hub on older mboards, sometimes they have one, or three on newer mboards.
Root Hubs for the USB 2.0 support always have more than three ports per Root Hub.
The total number of USB 1.1 Root Hub ports = the total number of USB 2.0 Root Hub ports - they are the same ports, dual purpose.
A device Windows "knows" works fine with only USB 1.1 support is only shown as drawing current in a USB 1.1 Root Hub.
A device Windows "knows" is supposed to work better if it has USB 2.0 support is often only shown as drawing current in a USB 2.0 Root Hub.
"I do have a card reader but I'm not sure how this fits into the equation."
Typically, a card reader connects to a header for one USB port connection on the mboard, however many types of cards it can read.
"Okay, same thing occurs with a different usb mouse and also a usb keyboard incidentally."
Is that ONLY when the USB sound adapter is plugged in ?
Is that when they are all plugged in ONLY to the USB ports built into the computer ?
" Now think it's probably a power issue with the OS/driver not intelligent enough to recognise when the sound adapter is being powered by its own power supply."
500ma x 5v = only 2.5 watts max available through the USB connection. The USB port supplies only 5v - the USB sound adapter may need another voltage such as 12v (what voltage is printed on the external power adapter ?) and far more current.
What are the input voltage(s) and current ratings the USB sound adapter needs ?
The OS has nothing to do with it.
If the laptop has a current per USB port problem, it's a hardware problem.
E.g. if the USB sound adapter works fine when it's the only thing plugged it, doesn't work fine when anything else is plugged in at the same time (I have NEVER heard of a USB connected keyboard conflicting with anything, and it draws very little power), if the USB adapter actually requires 500 ma via the USB connection, your laptop can't supply 500ma per port.
You could try using a USB Y cable with the USB sound adapter when you have another USB device plugged in, with two USB plugs on the computer end plugged in. If you already have an external 2.5" (e.g. "Portable") hard drive, you may already have a Y cable that will plug into the USB sound adapter. Otherwise, you can probably buy a suitable one locally.
"... being suggested that a PC card or express card would solve this (don't want to throw cash at this problem unless it will definitely work.."
They WILL solve your problem if your problem is due to your built in USB ports cannot supply 500ma per port, however, as I said above.....
"....all the ones I've examined the specs for support 500ma total current for all the ports, not each port, unless the adapter has a jack a 5v external power adapter can be plugged into and you plug one in."
The USB sound adapter will work for sure if it's the only thing plugged into the multiple ports for the device, but you may have the same problem when you plug in the USB adapter AND something else into the multiple ports for the device.
They are NOT expensive. If you live in a reasonably large city, local places often have them in stock.Otherwise, they are easily available on the web.