The select (S0, S1) inputs control the data path of each multiplexer/demultiplexer. The EN and TC inputs determine the internal termination for S0 and S1 inputs. When EN is low, the termination is determined by the TC input. When both EN and TC are low, termination resistors are disconnected from the S inputs. When EN is low and TC is high, both pullup and pulldown resistors are connected to the S inputs. When EN is high, only the pulldown termination resistors are connected to the S inputs, regardless of the voltage level at the TC input.