INTERBUS CT coupling modules connect two INTERBUS systems together on the input/output level. In their function, they correspond to two normal I/O modules, the inputs and outputs of which are connected crosswise. In this way, INTERBUS can be used to facilitate bi-directional data transfer between any two control systems. The extent of the data can be up to ten words (160 bits) per cycle. The data width can be configured between one byte and ten words by means of a rotary switch (byte configuration is only possible in Generation 4 controller boards). The selected data word (or byte) is shown on a 7-segment display. The modules are installed directly in the INTERBUS remote bus. In the case of the IBS CT 24 IO GT-LK-OPC fiber optic version, the bus is connected via F-SMA connectors. The modules are equipped with isolated bus lines, a redundant supply of the 24 V power, and optical path regulation. Sixteen status LEDs assigned to each bus line are used to display the signal states. A button located on the module permits the current output word or byte of the specific remote bus to be displayed. In this case, the output information for one bus is the input information of the other.