Module A-150 (Dual VCS) contains two separate voltage-controlled switches. 

Each switch has a control voltage input, a common Out / Input, and two In / Outputs. 

The switches are bi-directional: 
they can work in both directions, so can connect one input to either of two outputs, or either of two inputs to one output. 

Voltages in the range -12V...+12V at the O/I resp. I/O sockets can be processed by the module. 

Two LEDs show which in / output is active (ie. which is connected to the common out / input). 

technical details

Width: 4HP 

Connections per unit: 
CV input 
I/O 1 
I/O 2 
O/I