MPEP § 1834
(a) Any paper submitted by the applicant in the course of the international procedure provided for in the Treaty and these Regulations, other than the international application itself, shall, if not itself in the form of a letter, be accompanied by a letter identifying the international application to which it relates. The letter shall be signed by the applicant.
(b) If the requirements provided for in paragraph (a) are not complied with, the applicant shall be informed as to the non-compliance and invited to remedy the omission within a time limit fixed in the invitation. The time limit so fixed shall be reasonable in the circumstances; even where the time limit so fixed expires later than the time limit applying to the furnishing of the paper (or even if the latter time limit has already expired), it shall not be less than 10 days and not more than one month from the mailing of the invitation. If the omission is remedied within the time limit fixed in the invitation, the omission shall be disregarded; otherwise, the applicant shall be informed that the paper has been disregarded.
(c) Where non-compliance with the requirements provided for in paragraph (a) has been overlooked and the paper taken into account in the international procedure, the non-compliance shall be disregarded.
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Where any international application indicates two or more applicants, it shall be sufficient, for the purpose of identifying that application, to indicate, in any Form or correspondence relating to such application, the name of the applicant first named in the request. The provisions of the first sentence of this Section do not apply to the demand.
If the Office finds that papers, other than the international application itself, are not accompanied by a letter identifying the international application to which they relate, or are accompanied by an unsigned letter, or are furnished in the form of an unsigned letter, it notifies the applicant and invites him or her to remedy the omission. The Office disregards the said papers or letter if the omission is not remedied within the time limit fixed in the invitation (PCT Rule 92.1(b) ). If the omission has been overlooked and the paper taken into account, the omission is disregarded.
Where there is a sole applicant without an agent in an international application, correspondence will be sent to the applicant at his or her indicated address; or, if he or she has appointed one or more agents, to that agent or the first-mentioned of those agents; or, if he or she has not appointed an agent but has indicated a special address for notifications, at that special address.
Where there are two or more applicants who have appointed one or more common agents, correspondence will be addressed to that agent or the first-mentioned of those agents. Where no common agent has been appointed, correspondence will be addressed to the common representative (either the appointed common representative or the applicant who is considered to be the common representative (PCT Rule 90.2 ) at the indicated address; or, if the common representative has appointed one or more agents, to that agent or the first-mentioned of those agents; or, if the common representative has not appointed an agent but has indicated a special address for notifications, at that address.
The Priority Mail Express® procedure set forth at 37 CFR 1.10 applies to papers filed with the U.S. Patent and Trademark Office (USPTO) in international applications. Accordingly, papers filed with the USPTO in international applications will be accorded by the USPTO the "date accepted" indicated on the Priority Mail Express® mailing label as the date of filing in the USPTO if the provisions of 37 CFR 1.10 are complied with. See MPEP § 513.
If there is a question regarding the date of deposit, the Priority Mail Express® provisions of 37 CFR 1.10(c) - (e) require, in addition to using the Priority Mail Express® Post Office to Addressee service, an indication of the Priority Mail Express® mailing label number on each paper or fee. In situations wherein the correspondence includes several papers directed to the same application (for example, Request, description, claims, abstract, drawings, and other papers) the correspondence may be submitted with a cover or transmittal letter, which should itemize the papers. The cover or transmittal letter must have the Priority Mail Express® mailing label number thereon.
The certificate of mailing by first class mail procedure set forth at 37 CFR 1.8 differs from the 37 CFR 1.10 Priority Mail Express® procedure. See 37 CFR 1.8(a)(2)(i)(D) and (E). It is important to understand that the 37 CFR 1.8 certificate of mailing procedure CANNOT be used for filing any papers during the international stage if the date of deposit is desired. If the 37 CFR 1.8 certificate of mailing procedure is used, the paper and/or fee will be accorded the date of receipt in the USPTO unless the receipt date falls on a Saturday, Sunday, or federal holiday in which case the date of receipt will be the next succeeding day which is not a Saturday, Sunday, or federal holiday (37 CFR 1.6(a)(1) ). Accordingly, the certificate of mailing procedures of 37 CFR 1.8 are not available to have a submission during the international stage considered as timely filed if the submission is not physically received at the USPTO on or before the due date.
PCT Rule 92.4 provides that a national Office may receive documents by telegraph, teleprinter, or facsimile machine. However, the United States Patent and Trademark Office has not informed the International Bureau that it accepts such submissions other than facsimile transmissions. Accordingly, applicants may not currently file papers in international applications with the United States Patent and Trademark Office via telegraph or teleprinter.
Generally, any paper may be filed by facsimile transmission with certain exceptions which are identified in 37 CFR 1.6(d). It should be noted that a facsimile transmission of a document is not permitted and, if submitted, will not be accorded a date of receipt if the document is:
Facsimile transmission may be used to submit substitute sheets (other than color drawings), extensions of time, power of attorney, fee authorizations (other than the basic national fee), demands, response to written opinions, oaths or declarations, petitions, Article 34 amendments, and translations in international applications.
A Certificate of Transmission may be used as provided in 37 CFR 1.8(a)(1) except in the instances specifically excluded in 37 CFR 1.8(a)(2). Note particularly that the Certificate of Transmission cannot be used for the filing of an international application for patent or correspondence in an international application before the U.S. Receiving Office, the U.S. International Searching Authority, or the U.S. International Preliminary Examining Authority. Guidelines for facsimile transmission are clearly set forth in 37 CFR 1.6(d) and should be read before transmitting by facsimile machine.
A signature on a document received via facsimile in a permitted situation is acceptable as a proper signature. See PCT Rule 92.4(b) and 37 CFR 1.4(d)(1)(ii).
The receipt date of a document transmitted via facsimile is the date in the USPTO on which the transmission is completed, unless the receipt date is a Saturday, Sunday, or Federal holiday in which case the date of receipt will be the next succeeding day which is not a Saturday, Sunday, or Federal holiday (37 CFR 1.6(a)(3) ). See 37 CFR 1.6(d). Where a document is illegible or part of the document is not received, the document will be treated as not received to the extent that it is illegible or the transmission failed. See PCT Rule 92.4(c).
Delay or loss in the mail shall be excused when it is proven to the satisfaction of the receiving Office that the concerned letter or document was mailed at least five days before the expiration of the time limit. The mailing must have been by registered air mail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail (PCT Rule 82.1(a) to (c) ). PCT Rule 82 contains detailed provisions governing the situation where a letter arrives late or gets lost due to irregularities in the mail service, for example, because the mail service was interrupted due to a strike. The provisions operate to excuse failure to meet a time limit for filing a document for up to six months after the expiration of the time limit concerned, provided that the document was mailed at least five days before the expiration of the time limit. In order to take advantage of these provisions, the mailing must have been by registered airmail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail. Evidence is required to satisfy the Office, and a substitute document must be filed promptly—see PCT Rule 82.1(b) and (c) for details.
Special provisions apply to excuse delays in meeting time limits fixed in the PCT Regulations, and to extend time limits due to a general disruption experienced by an office or authority, caused by war, revolution, civil disorder, strike, natural calamity, epidemic, a general unavailability of electronic communications services or other like reasons. For example, a delay in meeting a time limit may be excused where the interested party establishes that an outage of electronic communications services affected a widespread geographical area, was unexpected or unforeseen, and that no alternative means of communication was available. See PCT Rule 82quater and PCT Administrative Instruction Section 111 for details.
See PCT Rule 80.5 for guidance on periods which expire on a non-working day.