This paper introduces the Resource Interface ontology intended to formally capture hardware interface information of production resources. It also proposes an interface matchmaking method, which uses this information to judge if two resources can be physically connected with each other. The matchmaking method works on two levels of detail, coarse and fine. The proposed Resource Interface ontology and matchmaking method can be utilised during production system design or reconfiguration by system integrators or end users. They will benefit from fast and automatic resource searches over large resource catalogues. In the end of the paper, a validation of the method is provided with a test ontology.