(a) Correspondence with the Patent and Trademark Office comprises:

(1) Correspondence relating to services and facilities of the Office, such as general inquiries, requests for publications supplied by the Office, orders for printed copies of patents, orders for copies of records, transmission of assignments for recording, and the like, and
(2) Correspondence in and relating to a particular application or other proceeding in the Office. See particularly the rules relating to the filing, processing, or other proceedings of national applications in subpart B of this part; of international applications in subpart C of this part; of ex parte reexaminations of patents in subpart D of this part; of supplemental examination of patents in subpart E of this part; of extension of patent term in subpart F of this part; of inter partes reexaminations of patents in subpart H of this part; of international design applications in subpart I of this part; and of the Patent Trial and Appeal Board in parts 41 and 42 of this chapter.

(b) Since each file must be complete in itself, a separate copy of every paper to be filed in a patent, patent file, or other proceeding must be furnished for each file to which the paper pertains, even though the contents of the papers filed in two or more files may be identical. The filing of duplicate copies of correspondence in the file of an application, patent, or other proceeding should be avoided, except in situations in which the Office requires the filing of duplicate copies. The Office may dispose of duplicate copies of correspondence in the file of an application, patent, or other proceeding.
(c) Since different matters may be considered by different branches or sections of the Office, each distinct subject, inquiry or order must be contained in a separate paper to avoid confusion and delay in answering papers dealing with different subjects. Subjects provided for on a single Office or World Intellectual Property Organization form may be contained in a single paper.
(d)

(1) Handwritten signature. Each piece of correspondence, except as provided in paragraphs (d)(2), (d)(3), (d)(4), (e) and (f) of this section, filed in an application, patent file, or other proceeding in the Office which requires a person’s signature, must:

(i) Be an original, that is, have an original handwritten signature personally signed, in permanent dark ink or its equivalent, by that person; or
(ii) Be a direct or indirect copy, such as a photocopy or facsimile transmission (§ 1.6(d)), of an original. In the event that a copy of the original is filed, the original should be retained as evidence of authenticity. If a question of authenticity arises, the Office may require submission of the original.

(2) S-signature. An S-signature is a signature inserted between forward slash marks, but not a handwritten signature as defined by paragraph (d)(1) of this section. An S-signature includes any signature made by electronic or mechanical means, and any other mode of making or applying a signature other than a handwritten signature as provided for in paragraph (d)(1) of this section. Correspondence being filed in the Office in paper, by facsimile transmission as provided in § 1.6(d), or via the Office electronic filing system as an attachment as provided in § 1.6(a)(4), for a patent application, patent, or a reexamination or supplemental examination proceeding may be S-signature signed instead of being personally signed (i.e., with a handwritten signature) as provided for in paragraph (d)(1) of this section. The requirements for an S-signature under this paragraph (d)(2) of this section are as follows.

(i) The S-signature must consist only of letters, or Arabic numerals, or both, with appropriate spaces and commas, periods, apostrophes, or hyphens for punctuation, and the person signing the correspondence must insert his or her own S-signature with a first single forward slash mark before, and a second single forward slash mark after, the S-signature (e.g., /Dr. James T. Jones, Jr./); and
(ii) A patent practitioner (§ 1.32(a)(1)), signing pursuant to §§ 1.33(b)(1) or 1.33(b)(2), must supply his/her registration number either as part of the S-signature, or immediately below or adjacent to the S-signature. The number (#) character may be used only as part of the S-signature when appearing before a practitioner’s registration number; otherwise the number character may not be used in an S-signature.
(iii) The signer’s name must be:

(A) Presented in printed or typed form preferably immediately below or adjacent the S-signature, and
(B) Reasonably specific enough so that the identity of the signer can be readily recognized.

(3) Electronically submitted correspondence. Correspondence permitted via the Office electronic filing system may be signed by a graphic representation of a handwritten signature as provided for in paragraph (d)(1) of this section or a graphic representation of an S-signature as provided for in paragraph (d)(2) of this section when it is submitted via the Office electronic filing system.
(4) Certifications—

(i) Certification as to the paper presented. The presentation to the Office (whether by signing, filing, submitting, or later advocating) of any paper by a party, whether a practitioner or non-practitioner, constitutes a certification under § 11.18(b) of this subchapter. Violations of § 11.18(b)(2) of this subchapter by a party, whether a practitioner or non-practitioner, may result in the imposition of sanctions under § 11.18(c) of this subchapter. Any practitioner violating § 11.18(b) of this subchapter may also be subject to disciplinary action. See § 11.18(d) of this subchapter.
(ii) Certifications as to the signature. The person inserting a signature under paragraph (d)(2) or (d)(3) of this section in a document submitted to the Office certifies that the inserted signature appearing in the document is his or her own signature. A person submitting a document signed by another under paragraph (d)(2) or (d)(3) of this section is obligated to have a reasonable basis to believe that the person whose signature is present on the document was actually inserted by that person, and should retain evidence of authenticity of the signature. Violations of the certification as to the signature of another or a person’s own signature as set forth in this paragraph may result in the imposition of sanctions under § 11.18(c) and (d) of this chapter.

(5) Forms. The Office provides forms for the public to use in certain situations to assist in the filing of correspondence for a certain purpose and to meet certain requirements for patent applications and proceedings. Use of the forms for purposes for which they were not designed is prohibited. No changes to certification statements on the Office forms (e.g., oath or declaration forms, terminal disclaimer forms, petition forms, and nonpublication request forms) may be made. The existing text of a form, other than a certification statement, may be modified, deleted, or added to, if all text identifying the form as an Office form is removed. The presentation to the Office (whether by signing, filing, submitting, or later advocating) of any Office form with text identifying the form as an Office form by a party, whether a practitioner or non-practitioner, constitutes a certification under § 11.18(b) of this chapter that the existing text and any certification statements on the form have not been altered other than permitted by EFS-Web customization.

(e) The following correspondence must be submitted with an original handwritten signature personally signed in permanent dark ink or its equivalent:

(1) Correspondence requiring a person's signature and relating to registration to practice before the Patent and Trademark Office in patent cases, enrollment and disciplinary investigations, or disciplinary proceedings; and
(2) Payments by credit cards where the payment is not being made via the Office's electronic filing systems.

(f) When a document that is required by statute to be certified must be filed, a copy, including a photocopy or facsimile transmission, of the certification is not acceptable.
(g) An applicant who has not made of record a registered attorney or agent may be required to state whether assistance was received in the preparation or prosecution of the patent application, for which any compensation or consideration was given or charged, and if so, to disclose the name or names of the person or persons providing such assistance. Assistance includes the preparation for the applicant of the specification and amendments or other papers to be filed in the Patent and Trademark Office, as well as other assistance in such matters, but does not include merely making drawings by draftsmen or stenographic services in typing papers.
(h) Ratification/confirmation/evidence of authenticity: The Office may require ratification, confirmation (which includes submission of a duplicate document but with a proper signature), or evidence of authenticity of a signature, such as when the Office has reasonable doubt as to the authenticity (veracity) of the signature, e.g., where there are variations of a signature, or where the signature and the typed or printed name, do not clearly identify the person signing.

(a) Date of receipt and Priority Mail Express® date of deposit. Correspondence received in the Patent and Trademark Office is stamped with the date of receipt except as follows:

(1) The Patent and Trademark Office is not open for the filing of correspondence on any day that is a Saturday, Sunday, or Federal holiday within the District of Columbia. Except for correspondence transmitted by facsimile under paragraph (a)(3) of this section, or filed electronically under paragraph (a)(4) of this section, no correspondence is received in the Office on Saturdays, Sundays, or Federal holidays within the District of Columbia.
(2) Correspondence filed in accordance with § 1.10 will be stamped with the date of deposit as Priority Mail Express® with the United States Postal Service.
(3) Correspondence transmitted by facsimile to the Patent and Trademark Office will be stamped with the date on which the complete transmission is received in the Patent and Trademark Office unless that date is a Saturday, Sunday, or Federal holiday within the District of Columbia, in which case the date stamped will be the next succeeding day which is not a Saturday, Sunday, or Federal holiday within the District of Columbia.
(4) Correspondence may be submitted using the Office electronic filing system only in accordance with the Office electronic filing system requirements. Correspondence submitted to the Office by way of the Office electronic filing system will be accorded a receipt date, which is the date the correspondence is received at the correspondence address for the Office set forth in § 1.1 when it was officially submitted.

(b) [Reserved]
(c) Correspondence delivered by hand. In addition to being mailed, correspondence may be delivered by hand during hours the Office is open to receive correspondence.
(d) Facsimile transmission. Except in the cases enumerated below, correspondence, including authorizations to charge a deposit account, may be transmitted by facsimile. The receipt date accorded to the correspondence will be the date on which the complete transmission is received in the United States Patent and Trademark Office, unless that date is a Saturday, Sunday, or Federal holiday within the District of Columbia. See paragraph (a)(3) of this section. To facilitate proper processing, each transmission session should be limited to correspondence to be filed in a single application or other proceeding before the United States Patent and Trademark Office. The application number of a patent application, the control number of a reexamination or supplemental examination proceeding, the interference number of an interference proceeding, the trial number of a trial proceeding before the Board, or the patent number of a patent should be entered as a part of the sender's identification on a facsimile cover sheet. Facsimile transmissions are not permitted and, if submitted, will not be accorded a date of receipt in the following situations:

(1) Correspondence as specified in § 1.4(e), requiring an original signature;
(2) Certified documents as specified in § 1.4(f);
(3) Correspondence that cannot receive the benefit of the certificate of mailing or transmission as specified in § 1.8(a)(2)(i)(A) through (D),(F), (I), and (K), and § 1.8(a)(2)(iii)(A), except that a continued prosecution application under § 1.53(d) may be transmitted to the Office by facsimile;
(4) Color drawings submitted under §§ 1.81, 1.83 through 1.85, 1.152, 1.165, 1.173, 1.437 , or 1.1026;
(5) A request for reexamination under § 1.510 or § 1.913 , or a request for supplemental examination under § 1.610 ;
(6) Correspondence to be filed in an application subject to a secrecy order under §§ 5.1 through 5.5 of this chapter and directly related to the secrecy order content of the application;
(7) In contested cases and trials before the Patent Trial and Appeal Board, except as the Board may expressly authorize.

(e) [Reserved]
(f) Facsimile transmission of a patent application under § 1.53(d). In the event that the Office has no evidence of receipt of an application under § 1.53(d) (a continued prosecution application) transmitted to the Office by facsimile transmission, the party who transmitted the application under § 1.53(d) may petition the Director to accord the application under § 1.53(d) a filing date as of the date the application under § 1.53(d) is shown to have been transmitted to and received in the Office,

(1) Provided that the party who transmitted such application under § 1.53(d):

(i) Informs the Office of the previous transmission of the application under § 1.53(d) promptly after becoming aware that the Office has no evidence of receipt of the application under § 1.53(d);
(ii) Supplies an additional copy of the previously transmitted application under § 1.53(d); and
(iii) Includes a statement which attests on a personal knowledge basis or to the satisfaction of the Director to the previous transmission of the application under § 1.53(d) and is accompanied by a copy of the sending unit’s report confirming transmission of the application under § 1.53(d) or evidence that came into being after the complete transmission and within one business day of the complete transmission of the application under § 1.53(d).

(2) The Office may require additional evidence to determine if the application under § 1.53(d) was transmitted to and received in the Office on the date in question.

(g) Submission of the national stage correspondence required by § 1.495 via the Office electronic filing system. In the event that the Office has no evidence of receipt of the national stage correspondence required by § 1.495, which was submitted to the Office by the Office electronic filing system, the party who submitted the correspondence may petition the Director to accord the national stage correspondence a receipt date as of the date the correspondence is shown to have been officially submitted to the Office.

(1) The petition of this paragraph (g) requires that the party who submitted such national stage correspondence:

(i) Informs the Office of the previous submission of the correspondence promptly after becoming aware that the Office has no evidence of receipt of the correspondence under § 1.495;
(ii) Supplies an additional copy of the previously submitted correspondence;
(iii) Includes a statement that attests on a personal knowledge basis, or to the satisfaction of the Director, that the correspondence was previously officially submitted; and
(iv) Supplies a copy of an acknowledgment receipt generated by the Office electronic filing system, or equivalent evidence, confirming the submission to support the statement of paragraph (g)(1)(iii) of this section.

(2) The Office may require additional evidence to determine if the national stage correspondence was submitted to the Office on the date in question.

For example, a facsimile transmission to the Office from California starting on a Friday at 8:45 p.m. Pacific time and taking 20 minutes, would be completed at 9:05 p.m. Pacific time. The complete transmission would be received in the Office around 12:05 a.m. Eastern time on Saturday. The receipt date accorded to the correspondence is the date of the following business day, which in this case, would be Monday (assuming that Monday was not a Federal holiday within the District of Columbia).

Note however, that if the Certificate of Transmission is available (for documents not proscribed by 37 CFR 1.8(a)(2)), then the above facsimile may be considered timely filed on Friday if it contains a Certificate of Transmission and is in compliance with 37 CFR 1.8(a)(1)(i)(B) and (ii).

For example, where a practitioner e-mails a 37 CFR 1.63 declaration to an inventor for signature by the inventor and receives an executed declaration by the inventor in return from the inventor, reasonable basis would exist.