A communication system comprising: a common communications device (900;1000;1100;1300;1400) comprising an array of near-field coupled resonant elements (110;210;310;410;510A,510B;610A, 610B,610C;710;810;1110;1210;1410), the resonant elements each comprising a coupling portion comprising a loop portion with free ends, a data transmission unit (520; 1191,1192); and a data reception unit (530;1191,1192), wherein each unit has a coupling portion (620,630;1120,1130), the units (520;530) being arranged to communicate with one another by means of the coupling portion (620,630;1120,1130) of each unit and the common communications device (900;1000;1100;1300;1400), the coupling portion of the data transmission unit comprises a resonant element comprising a loop portion arranged to be near-field coupled to the loop portion of a first resonant element of the common communications device, the coupling portion (620,630; 1120,1130) of the data reception unit (530; 1191,1192) comprising a resonant element comprising a loop portion arranged to be near-field coupled to the loop portion of a second resonant element of the common communications device not being the first resonant element; wherein the common communications device comprises first and second layers of resonant elements (110;210;310;410;510A,510B;610A,610B,610C;710;810;1110;1210;1410) and resonant elements (110;210;310;410;510A,510B; 610A,610B,610C;710;810;1110;1210;1410) of the first and second layers are provided at relative positions arranged to introduce coupling between layers thereby to enhance an amount of coupling between elements of a given layer. a common communications device (900;1000;1100;1300;1400) comprising an array of near-field coupled resonant elements (110;210;310;410;510A,510B;610A, 610B,610C;710;810;1110;1210;1410), the resonant elements each comprising a coupling portion comprising a loop portion with free ends, a data transmission unit (520; 1191,1192); and a data reception unit (530;1191,1192), wherein each unit has a coupling portion (620,630;1120,1130), the units (520;530) being arranged to communicate with one another by means of the coupling portion (620,630;1120,1130) of each unit and the common communications device (900;1000;1100;1300;1400), the coupling portion of the data transmission unit comprises a resonant element comprising a loop portion arranged to be near-field coupled to the loop portion of a first resonant element of the common communications device, the coupling portion (620,630; 1120,1130) of the data reception unit (530; 1191,1192) comprising a resonant element comprising a loop portion arranged to be near-field coupled to the loop portion of a second resonant element of the common communications device not being the first resonant element; wherein the common communications device comprises first and second layers of resonant elements (110;210;310;410;510A,510B;610A,610B,610C;710;810;1110;1210;1410) and resonant elements (110;210;310;410;510A,510B; 610A,610B,610C;710;810;1110;1210;1410) of the first and second layers are provided at relative positions arranged to introduce coupling between layers thereby to enhance an amount of coupling between elements of a given layer.