HACKINTOSH.ORG | Macintosh discussion forums

Devices disconnecting? It's about the hub, bub

<article>
   <section class="page">
<p>
Reader Micha Warwick has a problem with power. He writes:</p>

I recently purchased a powered 10-port USB hub because I have a lot of peripherals. I’ve used nearly all the ports for external devices—a web cam, some external drives, and so on. When I plug in my camera I see a message that one of my hard drives has been disconnected even though I haven't touched the cable or powered down the drive. Is the hub or drive broken?

<p>
No. In fact, the hub is operating exactly as it's supposed to.</p><p>
USB hubs like this are designed to provide only so much power—say 250mA (Milliamps) on average to 10 devices. As long as the power requirements of all the devices you jack into the hub fall under that aggregate limit, all 10 devices should be recognized. However, if you exceed the hub’s limits—you’ve plugged in several devices that draw 500mA, for example—something’s got to give. And generally, what gives is the disappearance of one of the connected devices, as evidenced by the disconnection message you’ve seen.</p><p class="jumpTag"><a href="/article/2449839/devices-disconnecting-its-about-the-hub-bub.html#jump">To read this article in full or to leave a comment, please click here[/url]</p></section></article>

Source: Devices disconnecting? It's about the hub, bub (http://www.macworld.com/article/2449839/devices-disconnecting-its-about-the-hub-bub.html#tk.rss_all)