The Beckhoff I/O system encompasses a large number of signals and functions. The extensive range of products is rounded off by system modules with additional functionalities: power supply modules for generating output voltages of 5 V DC, E-bus refreshment as well as placeholder and brake chopper modules.

In terms of technology, the EJxxxx EtherCAT plug-in modules are usually based on the ELxxxx EtherCAT Terminals with matching name. This allows initial tests to be carried out with EL terminals, while the corresponding EJ module on the signal distribution board is used in subsequent series production.