Aloha, I just got your e-mail "Is PC to iOS Data Transfer via cable possible without iTunes?" but it doesn't have an active return address.

To do the USB/Lightning connection with an iPad you need to first join Apple's MFi program which gives access to the resources for that:

https://developer.apple.com/programs/mfi/

Stephen, I"m glad you remember me!  I friended you because I wanted to reply to your usb question.  Next time create a post and it will be easier for folks to reply.  

It is not clear if you want simply transfer files or use the link with your app.  either is possible.  take a look at this for programatic xfer;  http://www.oodlestechnologies.com/blogs/Data-transfer-to-iOS-device...(using-USB-Multiplex-Daemon)

and I use Macroplant's iexplorer to xfer files and otherwise work with my iphone from my pc or mac, but there are other similar programs:  http://www.macroplant.com/iexplorer/

If you tell me a little more about what you're trying to do I'll see if I can help.

Ken

The only way a vanilla IOS app (developed by ordinary IOS Developers) can communicate externally seems to be via TCP (and only wirelessly?) or Bluetooth. Apple has an additional Made For Apple (MFi) licensing for hardware and software developers (separate programs, actually) who need to develop apps which connect to external devices via the Lightning connector (which includes USB), headphones and remotes, and to specialized wireless devices (e.g. watches). Redpark, for example, emphasizes that their gear is licensed under MFi (I don't how"special" their cable is, but their Rsc Mgr SDK that you need to integrate into your app to actually use the cable certainly is).

My first thought is that before diving into MFi, you should check to whether your app (and PC application) can use Bluetooth between the IOS device and PC. Bluetooth might or might not be constrained by whatever VPN configuration will be used concurrently (and, of course, whether or not all the PCs involved would have Bluetooth). If not, then you'll probably have no choice but to work with an existing MFi solution (like Redpark), or roll your own MFi solution -- both will probably involving some licensing fees.