Radio system with universal communication interface

A radio system comprises a radio ( 1 ) having a transmit mode activated by a press to talk (PTT) switch ( 16 ) mounted on a universal communication interface ( 12 ) for mounting on a radio interface ( 6 ) associated with the radio ( 1 ). The radio interface ( 6 ) may or may not form part of the radio ( 1 ) and a plurality of radio interfaces may be provided for different applications, such that a standard universal communication interface ( 12 ) can be used with different types of equipment.