An integrated circuit comprising: a plurality of radio circuits (112, 114), wherein each radio circuit includes: a radio circuit input (2,4,6, 102B, 106B) configured to receive radio frequency, RF, signals from a respective receiver; a radio circuit output (92,94,96,102A,106A) configured to output RF signals to a respective transmitter; a switching network for performing a built-in-self-test, BIST, procedure; and circuitry configured to control the switching network to perform said BIST procedure, wherein the switching network comprises: a plurality of combiners (22,24,26), each combiner having an input (21A, 23A, 25A) and an output (21B, 23B, 25B); a plurality of transmitter connection switches (12,14,16), wherein each transmitter connection switch is operable selectively to couple each radio circuit output to the input (21A, 23A, 25A) of each of said combiners; a combiner switch having an input and an output, wherein the input is coupled to the output (21B, 23B, 25B) of each combiner (22,24,26), wherein the combiner switch is operable selectively to output an output signal received from each of said combiners (22,24,26); a splitter switch having an input and an output, wherein the input of the splitter switch is coupled to an output of the combiner switch via one or more further switches (42,52); a plurality of splitters (72,74,76), each splitter having an input (71A, 73A, 75A) and an output (71B, 73B, 75B), wherein the input of each splitter is coupled to the output of the splitter switch, wherein the splitter switch is operable selectively to output an output signal received from the one or more further switches (42,52) to one of said splitters; characterised in that the integrated circuit further comprises a plurality of receiver connection switches (82,84,86), wherein each receiver connection switch is operable selectively to couple the output (71B, 73B, 75B) of each splitter (72,74,76) to one of said radio circuit inputs. a plurality of radio circuits (112, 114), wherein each radio circuit includes: a radio circuit input (2,4,6, 102B, 106B) configured to receive radio frequency, RF, signals from a respective receiver; a radio circuit output (92,94,96,102A,106A) configured to output RF signals to a respective transmitter; a radio circuit input (2,4,6, 102B, 106B) configured to receive radio frequency, RF, signals from a respective receiver; a radio circuit output (92,94,96,102A,106A) configured to output RF signals to a respective transmitter; a switching network for performing a built-in-self-test, BIST, procedure; and circuitry configured to control the switching network to perform said BIST procedure, a plurality of combiners (22,24,26), each combiner having an input (21A, 23A, 25A) and an output (21B, 23B, 25B); a plurality of transmitter connection switches (12,14,16), wherein each transmitter connection switch is operable selectively to couple each radio circuit output to the input (21A, 23A, 25A) of each of said combiners; a combiner switch having an input and an output, wherein the input is coupled to the output (21B, 23B, 25B) of each combiner (22,24,26), wherein the combiner switch is operable selectively to output an output signal received from each of said combiners (22,24,26); a splitter switch having an input and an output, wherein the input of the splitter switch is coupled to an output of the combiner switch via one or more further switches (42,52); a plurality of splitters (72,74,76), each splitter having an input (71A, 73A, 75A) and an output (71B, 73B, 75B), wherein the input of each splitter is coupled to the output of the splitter switch, wherein the splitter switch is operable selectively to output an output signal received from the one or more further switches (42,52) to one of said splitters; characterised in that the integrated circuit further comprises a plurality of receiver connection switches (82,84,86), wherein each receiver connection switch is operable selectively to couple the output (71B, 73B, 75B) of each splitter (72,74,76) to one of said radio circuit inputs.