The pin resp. signal assignment results from the combination with an electronic module. You find the pin configuration and the wiring diagrams on the data sheet of the corresponding electronic module. BL67 Base Modules are connected to the right of the gateway, using two screws for each module. A DIN rail is not required. This way, a compact and stable unit is built. The unit can now be mounted on a DIN rail or directly on the machine. The field devices are connected to the Base Modules which are available with different connection technology (M8, M12, M23 and 7/8 in).