Techniques and methods for determining the number and type of leads that are connected to an implantable medical device (IMD) system are disclosed. The IMD system is configured having at least two modes of operation, the modes of operation corresponding to the number and type of leads that are coupled to the IMD system. In accordance with aspects of the disclosure, one of the at least two modes may be selected based on the determination of the number and type of leads that are connected to the IMD system.