DECA Automation Products DECA is a manufacturer of automation products ; switches, pilot light, emergency switch & terminal blocks. These automation products are widely use in machine tools, industrial and factory automation industries. Dia. 16mm Control Units - DECADia. 22mm ControlUnits - DECAD-Sub Interface Terminals (Female) - DECAD-Sub Interface Terminal (Male) - DECAIDC Connector Terminals - DECAInterface Relay Board - DECADin-Rail Feed Through Terminal Blocks - DECACam Switches - DECA