A semiconductor chip having a functional block that performs a communication function includes an input circuit that supplies an oscillating test signal to the functional block, and a test circuit that detects the strength of an oscillating signal which the functional block outputs in response. A strength signal indicating the detected strength is output from the test circuit through an external terminal of the semiconductor chip to a test device. The test device evaluates the strength signal to decide whether an operating characteristic of the functional block is within a specified range. The strength information indicated by the strength signal is not affected by impedance on the signal transmission line between the semiconductor chip and the test device, so the test is not affected by impedance loss.