Error-tolerance deals with the use of defective circuitry that occasionally produces errors, yet provides acceptable performance to end users when executing certain applications. The motivation for using such devices is the related increase in effective yield, and hence lower cost parts. We present a framework for the analysis of the applicability of error-tolerance. The framework is illustrated with respect to a digital telephone-answering device, but is applicable to a broad class of multi-media systems. Key components of this framework are: defining acceptable yet imperfect behavior; determining if a large class of realistic defects in a subsystem provide acceptable behavior at the system level; and determining how to recognize (test) if a defective subsystem will provide acceptable system performance.