What methods are available for connecting a hardware accessory to iphone and android devices to transfer data?

Question

I am trying to develop a piece of hardware to be compatible with both iphone and android devices. I would like to be able to use this hardware to transfer binary type files (i.e. images) to the device so the highest bandwidth option would be best choice.

It looks like android supports usb/bluetooth profiles as of 3.0+. I haven't been able to find out much information for the iphone other than the bluetooth is restricted.

Any information, links etc. would be extremely helpful. Thank you in advance for your help.

Answer 1

WiFi, modulated audio (such as FSK), images (such as QR codes), and joining Apple's MFi program for non-public info on other possible methods (Bluetooth data profiles and the dock connector).