Quality assurance systems and ISO 9001 in particular have received a lot of attention in recent times, much of which is negative. Here we examine a more positive example and look at the role that ISO 9001 has played in embedded software development at Pi Technology. In this paper we address the following points. What the purpose of a quality system is or at least should be. Why we introduced a quality system and how we went about developing and implementing the system. We examine the pit falls we avoided and those we didn't and look at the positive benefits we believe we see from having a quality system in operation. We also generalise the lessons we have learnt to other quality systems such as CMM.