In T 154/04 the board stated that a non-technical feature may interact with technical elements so as to produce a technical effect, e.g. by its application in the technical solution of a technical problem. Non-technical features, to the extent that they do not interact with the technical subject matter of the claim for solving a technical problem, i.e. non-technical features "as such", do not provide a technical contribution to the prior art and are thus ignored in assessing novelty and inventive step. This is the approach used by board in T 154/04 (OJ 2008, 46) to determine the technical features in a claim if technical and non-technical aspects are tightly intermingled in a mixed type claim, as is typically the case with computer-implemented inventions (see, for example, decisions T 619/02 and T 172/03) (see also T 641/00, OJ 2003, 352; T 1505/05; T 477/08; T 1358/09).

In T 603/89 (OJ 1992, 230) the board pointed out that the subject-matter of a "mix" claim is not excluded from patentability under Art. 52(2) and (3) EPC 1973 when, but only when, the non-technical elements interacted with the known technical elements in order to produce a technical effect (see T 26/86, OJ 1988, 19). In the absence of such an interaction – when the technical elements were only a support for the non-technical elements but did not otherwise co-operate therewith – the invention did not make use of technical means and could not therefore be granted (see T 158/88, OJ 1991, 566; T 1670/07).