Radio broadcasting has entered the digital era, where services are delivered from the studio to the listener entirely in the digital domain. The Satellite Digital Audio Receiver Systems (SDARS) being developed provides the means to receive high-quality digital radio services. The SDARS receiver will be a peripheral component to the existing audio system in the vehicle for the first generation. Subsequent generations of the product will examine the opportunity for up-integrating the SDARS receiver into the modules of existing entertainment system. This paper will outline a set of common operating characteristics that may be used in peripheral SDAR applications. If adhered to, this will allow the XM Satellite Radio service and Sirius Satellite Radio service to co-habitat on the same audio system or be interchangeable at a receiver module level. Many of the points discussed in this paper are not specific to or under the control of the SDARs service providers. Some items require compliance with existing vehicle practices while others are new to the automotive environment.