USB On-The-Go - What receptacle types does it support?
As stated by Wikipedia [USB OTG]

"An OTG product must have a single micro-AB receptacle and no other USB receptacles. 

An OTG cable has a micro-A plug on one end, and a micro-B plug on the other end (it cannot have two plugs of the same type). OTG adds a fifth pin to the standard USB connector, called the ID-pin; the micro-A plug has the ID pin grounded, while the ID in the micro-B plug is floating. A device with a micro-A plug inserted becomes an OTG A-device, and a device with a micro-B plug inserted becomes a B-device. The type of plug inserted is detected by the state of the pin ID."

There are several other sources which have information about USB OTG.

USB On-The-Go Specification