Wis. Stat. § 134.35: Time of filing endorsed on telegrams delivered.

(1) Every person, firm or corporation operating a telegraph line or lines in this state shall, without extra charge therefor, cause to be written, stamped or printed in a conspicuous place upon the addressee’s copy of each telegram originating at and destined to a point within this state, the hour and minute of the day in which the copy of such telegram was filed or left with such person, firm or corporation for transmission and the hour and minute of the day when such telegram was received in the office of such person, firm or corporation at its destination.

(2) Any person, firm or corporation violating any of the provisions of this section shall be deemed guilty of a misdemeanor.