The CGS54 is intended an add-on for the CGS36 Pulse Divider and Boolean Logic module, adding XOR and XNOR functionality. Unlike a true digital gate, the module is not sensitive to specific levels, but rather to the difference between them. If the two inputs are within approximately approximately 1.2 volts of each other, they are regarded as being the same logical value. If they are more than approximately 1.2 volts apart, they are regarded as being different. This means that while this module will work quite satisfactorily with any logic levels, it can also be used to compare two analog signals, either positive or negative in value. If only one input is connected, the output will be the same as if two identical inputs were present.
CGS54 Datasheet and Build Guide