This paper aims at presenting the hardware and software design of an experimental system allowing the inclusion of speech capabilities at the man-machine interface level. That experimental system is made of a workstation and of a SPeech INterface (SPIN) connected to the workstation via a serial link and acting as a complete interface for applications in which speech is involved; the SPeech INterface includes indeed all the elements of speech processing, speaker verification, speech coding and text-to-speech synthesis.