  This is a review paper updated from that presented for CAS 2004. Essentially,
since then, commercial components have continued to extend their performance
boundaries but the basic building blocks and the techniques for choosing the
best device and implementing it in a design have not changed. Analogue to
digital and digital to analogue converters are crucial components in the
continued drive to replace analogue circuitry with more controllable and less
costly digital processing. This paper discusses the technologies available to
perform in the likely measurement and control applications that arise within
accelerators. It covers much of the terminology and 'specmanship' together with
an application-oriented analysis of the realisable performance of the various
types. Finally, some hints and warnings on system integration problems are
given.
