A semiconductor integrated circuit has a squelch circuit which has a first noninverting input terminal and a first inverting input terminal, which compares differential amplitude between a signal which is input to the first noninverting input terminal and a signal which is input to the first inverting input terminal with a preset threshold, and which outputs a signal depending upon a result of the comparison. The semiconductor integrated circuit has a first switch circuit between a first reception terminal and the first noninverting input terminal. The semiconductor integrated circuit has a second switch circuit between a second reception terminal and the first inverting input terminal. The semiconductor integrated circuit has a third switch circuit between the first reception terminal and the first inverting input terminal. The semiconductor integrated circuit has a fourth switch circuit between the second reception terminal and the first noninverting input terminal.