37 CFR §11.42

1. (a)All papers other than a complaint shall be served on a respondent who is represented by an attorney by:
   1. (1)Delivering a copy of the paper to the office of the attorney; or
   2. (2)Mailing a copy of the paper by first-class mail, Priority Mail Express®, or other delivery service to the attorney at the address provided by the attorney under § 11.40(a)(1); or
   3. (3)Any other method mutually agreeable to the attorney and a representative for the OED Director.
2. (b)All papers other than a complaint shall be served on a respondent who is not represented by an attorney by:
   1. (1)Delivering a copy of the paper to the respondent; or
   2. (2)Mailing a copy of the paper by first-class mail, Priority Mail Express®, or other delivery service to the respondent at the address to which a complaint may be served or such other address as may be designated in writing by the respondent; or
   3. (3)Any other method mutually agreeable to the respondent and a representative for the OED Director.
3. (c)A respondent shall serve on the representative for the OED Director one copy of each paper filed with the hearing officer or the OED Director. A paper may be served on the representative for the OED Director by:
   1. (1)Delivering a copy of the paper to the representative; or
   2. (2)Mailing a copy of the paper by first-class mail, Priority Mail Express®, or other delivery service to an address designated in writing by the representative; or
   3. (3)Any other method mutually agreeable to the respondent and the representative.
4. (d)Each paper filed in a disciplinary proceeding shall contain therein a certificate of service indicating:
   1. (1)The date on which service was made; and
   2. (2)The method by which service was made.
5. (e)The hearing officer or the USPTO Director may require that a paper be served by hand or by Priority Mail Express®.
6. (f)Service by mail is completed when the paper mailed in the United States is placed into the custody of the U.S. Postal Service.