9th September 2002

Question: My PC only has two USB connections so I bought a USB hub to alleviate this problem. For some reason, however, my Sandisk cardreader and my Microsoft Intellimouse will not work on the hub. Why will some USB periphials work through a hub while others will not and is there a fix for this?

Answer: I can't say that I have personally run into this problem, but I have heard it echoed by several other USB usersEverything I write after this sentence is my educated opinion. It may not be correct, but I did do some research on this subject so all my opinions are based on some technical fact. First, I would need to know if you are using a powered USB hub, by that I mean do you plug it in to an electrical outlet? USB cables have 4 pins; one for ground, two for data, and one +5 volt power. Your cardreader and mouse should both get their power from the computer (through the USB bus), otherwise you have to plug in a separate power adapter for each unit. So it is possiblity, although a small one, that these units aren't getting the proper amount of power through the USB hub. If it is a powered hub then this probably isn't the problem. Another possibility is that your computer isn't assigning each of the USB devices on the hub an address (this is called enumeration). This could be a bad/incompatible USB hub or your machine might not recognize the USB hub. I have never seen a USB hub come with software/drivers but if your hub did then you may need to install them and that should fix the problem. The main thing I would have you try is to plug into the USB hub a USB device like a printer which gets its power from a separate power adapter. If the device works then you know it is a power issue and I would contact the USB hub manufacturer. If that doesn't get you anywhere, I would say try another hub.