Module A-182-4 is a simple passive module that contains two mechanical rotary switches with 4 positions each. According to the position of the control knob socket 1, 2, 3 or 4 is connected to the common socket C.
As the module is fully passive it works bidirectional, i.e. the sockets 1...4 can be inputs and then C is the output. The other way round C can be the input and the sockets 1...4 are the outputs.
By means of an internal jumper the terminals C of both switches can be connected. That way the module can be used as kind of a miniature 4x4 matrix. Rotary switch A is e.g. used to select one of the four sockets 1...4 as input and this signal is sent to one of the four sockets 1...4 of switch B.