Arduino ADK R3 CTS Pin


I am investigating attaching an ANT Wireless Module to a Arduino ADK R3.

The ANT Interface Guide discusses two methods of interfacing; Synchronous Serial Interface and Asynchronous Serial Interface.

The Asynchronous Serial Interface requires that the Microcontroller was a CTS, TX and RX Pins.

Where is the CTS Pin on an Arduino ADK R3 Board?

Does one exist?