September 5, 2000
The Office of Government Ethics is amending the prohibition on employees' receipt of compensation for outside teaching, speaking, and writing, as set forth in the Standards of Ethical Conduct for Employees of the Executive Branch, to permit acceptance of travel expenses by employees other than covered noncareer employees.
https://www.govinfo.gov/content/pkg/FR-2000-09-05/pdf/00-22612.pdf