In T 442/91 the respondents wanted the board to rule on the extent of the protection conferred by what they considered to be broad claims. The board observed that the EPO concerned itself in opposition appeal proceedings with the extent of protection conferred by a patent only for the purposes of examining compliance with Art. 123(3) EPC 1973. Beyond that, interpreting the extent of protection was a matter for national courts dealing with infringement cases. Whilst the EPO made it clear how terms of art used in the claims should be understood, it should not proffer any further interpretation of the patent's future scope beyond that (see also T 740/96). In line with this thinking, the board in T 439/92 and T 62/92 interpreted the claims with a view to identifying their subject-matter.