We hold that a district court may rely on an industry standard in analyzing infringement. If a district court construes the claims and finds that the reach of the claims includes any device that practices a standard, then this can be sufficient for a finding of infringement. We agree that claims should be compared to the accused product to determine infringement. However, if an ac-cused product operates in accordance with a standard, then comparing the claims to that standard is the same as comparing the claims to the accused product. We ac-cepted this approach in Dynacore where the court held a claim not infringed by comparing it to an industry stan-dard rather than an accused product. An accused in-fringer is free to either prove that the claims do not cover all implementations of the standard or to prove that it does not practice the standard.
* * *
We acknowledge, however, that in many instances, an industry standard does not provide the level of specificity required to establish that practicing that standard would always result in infringement. Or, as with the ’952 pat-ent, the relevant section of the standard is optional, and standards compliance alone would not establish that the accused infringer chooses to implement the optional section. In these instances, it is not sufficient for the patent owner to establish infringement by arguing that the product admittedly practices the standard, therefore it infringes. In these cases, the patent owner must com-pare the claims to the accused products or, if appropriate, prove that the accused products implement any relevant optional sections of the standard. This should alleviate any concern about the use of standard compliance in assessing patent infringement. Only in the situation where a patent covers every possible implementation of a standard will it be enough to prove infringement by showing standard compliance.