Hey there User8675309,
It sounds like your 2 devices suddenly are not recognized on any computer with any USB cable you have tried. I think you did a great job of troubleshooting so far, I would agree the cables are not going to be the issue here. Assuming you have already restarted the devices:
Turn your iOS device off and on (restart) and reset
http://support.apple.com/kb/ht1430
I would start by using the following article to help troubleshoot the iTunes software and iOS drivers on one of the computers:
iOS: Device not recognized in iTunes for Windows
http://support.apple.com/kb/ts1538
Or, if you have Mac OS X:
iOS: Device not recognized in iTunes for Mac OS X
http://support.apple.com/kb/ts1591
If the issue persists, I would next try these steps from the following article:
- Remove any third-party battery packs or cases from the device and ensure that the USB cable is connected directly to the port on the device.
- If your Lightning or 30-pin cable is connected to a keyboard, display or USB hub, try plugging it directly into a USB port on the computer instead.
- Close any virtualization apps (such as Parallels or VMWare).
These apps may interfere with your computer's ability to communicate over USB if they aren't properly configured, or up to date. If this resolves the issue, contact the developer of the app to see if an update is available.
- Restart your computer.
- Restart your iPad, iPhone, or iPod touch.
- If you're using an accessory or third-party cable to connect your device, try using an Apple cable with the device instead.
- Update to the latest version of iTunes if you have not already.
- Disconnect other USB devices from your computer, except for your keyboard and mouse. Then, reconnect your iOS device. If the issue is resolved, reconnect the other USB devices one at a time. Make sure your iOS device is still recognized by the computer after adding back each device.
If one of these steps resolves the issue, but it comes back later, make sure you haven't changed how the device is connected. For example, check to see if you plugged the device into a specific accessory, or used a specific cable that reintroduced the issue.
From: iOS: Troubleshooting USB-related alerts when syncing
http://support.apple.com/kb/TS5254?viewlocale=en_US
Thank you for using Apple Support Communities.
All the very best,
Sterling