An interface circuit includes a signal processing circuit including multiple signal processing devices and a monitor and calibration module. The monitor and calibration module includes multiple monitor circuits, a processor and a calibration circuit. The monitor circuits monitor at least one of an amplitude, a frequency and a jitter in at least one of a reception signal and a transmission signal to correspondingly generate a monitored result and monitor at least one of power supplying voltage and ground voltage to correspondingly generate a monitored result. The processor collects the monitored results and determines a calibration operation based on the monitored results. The calibration circuit is coupled to the processor and at least one signal processing device and performs the calibration operation on the signal processing device to adjust a characteristic value of the signal processing device.