At the plant end, signal cables can be connected to the FM 458-1 DP modules using interface modules. The FM 458-1 DP has no screw terminals for direct connection of signal cables.

Each interface module has an interface cable (type SC..., 2 m long) with which it can be connected to the FM module.

Information on the interface modules which can be used for a specific module, as well as the required connecting cables, can be obtained from the planning guidelines (connection diagrams). Depending on their function, some of the interface modules have electronics which must be provided with an external voltage (commercially available power supply units).