The European Patent Convention (EPC) is an international treaty between European countries.
For the Contracting States, the EPC establishes a European Patent Organisation ("EPO") and a uniform system for the filing and grant of patents. Such "European Patents" have in each of the Contracting States the effect of a national patent granted by that State, and is subject to the same national conditions (cf. Article 2 para 2 EPC).
The procedure in case of an infringement of a European Patent follows the national legal system of the Contracting State concerned.
The Patent Cooperation Treaty (PCT) is an international treaty and provides the possibility to file one single patent application (an "international" patent application) that has the same effect as a national patent application in more than 120 States, instead of filing multiple national or regional patent applications. Only after a delay of at least 30 months, the national or regional procedures are to be started in the desired States or regions. Within this period, the applicant receives an official opinion regarding patentability of the invention and has time to decide whether and in which countries respectively he wants to enter the national or regional phase. Accordingly, the prosecution costs in the desired States or regions are delayed.