USB Host is a pretty useful feature to have on a smartphone, but also a feature that has so far been pretty rare on HTCâ€™s devices.
It is therefore of interest when they apply for a patent for an adaptor which makes USB Host a little bit easier. The adaptor allows one to power the smartphone at the same time as powering the USB accessory using the same port.
It is of interest that the HTC HD2, which does have USB Host, will only function if the device plugged is powered externally suggesting that HTC may have intended to release this accessory at some point.
See the patent here.