The interface connection mechanism has an analogue input/output unit (100) connected to a device using analogue circuits (TA). This is connected to an analogue signal processor (200,230,250). The processed analogue signals are passed to an analogue to digital (A/ D) convertor (300). The digital output is processed (400) by a unit which preferably includes a microprocessor and a memory loaded with an application program. The processed output is passed to a digital input/output interface (500), connecting to the mobile telephone network. Preferably the interface connection device includes an digital to analogue converter for use with a bi-directional communication.