According to Art. 133(1) EPC, no person shall be compelled to be represented by a professional representative in proceedings established by the EPC. However, Art. 133(2) EPC stipulates that natural or legal persons not having either a contracting state residence or their principal place of business within the territory of one of the contracting states must be represented by a professional representative and act through him in all proceedings established by the Convention (T 1157/01 reviews the applicable law), other than in filing the European patent application (see T 451/89 and T 883/90). The Implementing Regulations may permit other exceptions.
In T 213/89 the Japanese inventor replied directly to the EPO with a set of revised application documents, and accompanied by a letter to his representative indicating that the revised documents had also been sent to the representative. The board noted that no confirmation by the representative was received that any of the submissions directly received from the inventor should be regarded as an official reply to an EPO action. Since persons not having a residence or their principal place of business within the territory of one of the contracting states must act through their representative in the proceedings, the said submissions received direct could not be taken into account.
Likewise in T 717/04, the representative lodged the appeal for the applicant on 11 March 2004 and paid the prescribed appeal fee simultaneously. The statement of grounds of appeal was received on 18 May 2004. On 27 February 2007, a letter from the appealing applicant, a natural person with an address not within the territory of one of the contracting states, was faxed to the EPO with arguments and a new set of claims to be taken into account. According to Art. 133(2) EPC 1973, since the appealing applicant's address was not within the territory of one of the contracting states, the board concluded that filing claims and arguments such as those in the appealing applicant's letter of 27 February 2007 would have required professional representation. As these submissions were neither made nor endorsed by the representative, the board could not take them into account.