Heads up for iMac users with digital cameras

[giza]

When trying to copy images off of my digital camera (a Sony Cybershot) earlier tonight, I began getting I/O errors, something I had never seen before. Yet, I could still pull up the pictures just fine on the camera.

I did a little troubleshooting and discovered that the unpowered USB ports in my keyboard might be the culprit. To the best of my understanding, there's nothing inherently wrong with unpowered USB, but some devices do require external power. This seemed to be confirmed when I plugged the USB cable into one of the powered ports on the back of the machine and not only was able to copy all the photos off, but with about twice the speed compared to before.

It's unclear whether my camera actually requires a powered USB port, but I think that a combination of: aging cables, aging camera, aging batteries, and aging memory card created enough resistance and/or signal loss on the cable for the lack of power to be a problem.

Oh well, I got all of my pictures off the camera, so it's not a big inconvenience. (watch my hard disk crash now! :-P)

Comments

[furahi.livejournal.com]

::stands back to see (and hear) your hard disk go boom::

[camstone.livejournal.com]

Actually, I've had this happen with some "inexpensive" cables/cable extensions. If they have a higher resistance - they can essentially drop the power level (and signal level) to a point that is too low. Digital cameras and scanners are notorious for this sort of problem. Unpowered hubs in the way can also cause this to occur if there are multiple devices hung off the same, singular powered line.

And yeah, when in doubt - direct connect to a powered USB.

[giza.livejournal.com]

Something I should mention is that when not in use, I coil the cable and store it with my camera. I can't help but wonder if it get damaged. :-/

[camstone.livejournal.com]

If it's tightly coiled, then yes. Especially watch at the ends of the cable where the connectors are... they tend to fail regularly. The mini-usb connectors especially. =(

[wildw0lf.livejournal.com]

Did the camera ever work before plugged into the usb port on the keyboard?

The port on the keyboard might be defective, but I've also found that the majority of the time, anything more than a mouse tends to require external power when plugged into the keyboard, or else you have to use the ports on the computer that provide more power - just what you discovered.

[giza.livejournal.com]

Oh yeah, I've had the camera for 2 years and had been hanging it off of the keyboard for the last year.

The only other thing is that this keyboard is the replacement keyboard that I got the other week, and the first time I used it with this camera. It's possible that either the keyboard was defective (less likely) or I was operating the camera out of spec the whole time, and this keyboard's USB connectors had just a little more impedience. (more likely)

[taral.livejournal.com]

You know what's funny? The USB specification is *very* strict about cable length and resistance, device power drain, and appropriate voltage levels. Doesn't surprise me that people would cut corners.

[taral.livejournal.com]

Also of note is that, IIRC, the USB spec says that low-power devices must have a "captive cable", i.e. a cable that cannot be disconnected from the device itself.

[giza.livejournal.com]

Fascinating. That would explain why my mouse cannot be disconnected and works just fine whenI plug it into the unpowered (keyboard) port.

[isteillia.livejournal.com]

Hi! stumbled on your lj, and would like to add you. Do you mind?

[giza.livejournal.com]

Not at all. Feel free to add me if you like.