37 C.F.R. § 2.191 Business to be transacted in writing.
Title 37 - Patents, Trademarks, and Copyrights
All business with the Office should be transacted in writing. The personal appearance of applicants or their representatives at the Office is unnecessary. The action of the Office will be based exclusively on the written record. No attention will be paid to any alleged oral promise, stipulation, or understanding in relation to which there is disagreement or doubt. The Office encourages parties to file documents through TEAS wherever possible.
Title 37: Patents, Trademarks, and Copyrights
PART 2—RULES OF PRACTICE IN TRADEMARK CASES
General Information and Correspondence in Trademark Cases
§ 2.191 Business to be transacted in writing.
