CD74HC4067 CMOS 16 Channel Digital Analog Multiplexer Breakout
It works with both digital and analog signals (the voltage can't be higher than VCC)
It internally routes the common pin (COM in the schematic, SIG on the board) to one of 16 channel pins (CHANxx).
The internal switches are bidirectional, support voltages between ground and VCC, have low “on” resistance and low “off” leakage, and to prevent crosstalk, perform “break-before-make” switching.
The mux/demux works with digital signals, you can use it to pipe TTL-level serial data to or from multiple devices.