D.C. Mun. Regs. tit. 19, r. 19-2132
The timekeeper shall sit at ringside closest to the gong. The timekeeper shall indicate the beginning and end of each round by striking the gong once with a metal hammer.
The timekeeper may have a whistle and an accurate stopwatch that an inspector of the Commission has examined and certified.
The timekeeper shall warn the seconds of the contestants by blowing a whistle ten (10) seconds before the beginning of each round.
Prior to starting a contest the referee shall obtain from each contestant the name of the chief second. The referee shall hold that chief second responsible for the conduct of the assistant seconds during the contest.
A referee shall wear solid dark trousers, a gray shirt with elbow length sleeves and collar, and a black bow tie, and standard low-cut boxing shoes.
D.C. Mun. Regs. tit. 19, r. 19-2132