Systems to confirm authenticity of electrodes and to provide compatibility between a medical device and associated electrodes are described. The systems include an electrode connector that stores an authentication code that is accessible to the medical device when the electrode connector is coupled to the medical device. The medical device uses the authentication code to determine an authenticity of the coupled electrodes. The electrode connector also includes physical features of a housing that allow the electrode connector to couple to different versions (e.g., older and new models) of the type of medical device. This feature allows reverse compatibility of the electrode connector to different versions of medical devices.