second sensor 203 is coupled to the second port of the analogue multiplexer 208 finally a last signal 206 from the last sensor 205 is coupled to the last port of the analogue multiplexer 208 a control signal 212 controls the analogue multiplexer 208 to select one of the analogue signals to form signal 209 which is coupled to the input of the analogue to digital converter 210 which then produces the digital output signal 211 as was stated earlier the sensors 201 203 and 205 may be a combination of biological parameter monitoring sensors and instrument monitoring sensors those who are familiar with the art readily understand that not all circumstances of converting a plurality of sensor data individually to a digital signal can be accomplished by the converter of fig2 alone situations exist wherein one or more sensors may have a digital signal output while others have an analogue signal output in such situations it will be necessary to perform the overall function of converting each sensor signal individually to a single digital signal by making use of a combination of analogue multiplexers digital multiplexers and analogue to digital converters referring back to fig1 the transmitter 120 receives the digital data stream 119 from processor 117 producing a modulated rf output signal 121 in practice such a transmitter requires at least a carrier generator for frequency modulation fm and binary frequency shift key bfsk applications the transmitter 301 described schematically in fig3 is capable of producing fm and bfsk modulated rf signals a carrier generator 303 such as an oscillator is shifted in frequency.