Parking meters shall be of either the penny, nickel, dime, quarter, or combination type and shall be so designed and constructed as to display a signal showing lawful parking following the deposit therein of a prescribed coin of the United States of America during the period of time for parking provided for the denomination of the coin so deposited, which in no event shall exceed the parking limits now or hereafter provided for the part of the street upon which the meter is placed. Each meter shall bear a sign or legend setting forth the denomination or denominations of coins which can be so deposited therein, and the parking time secured thereby, which sign or legend may be in lieu of any other sign pertaining to the parking of vehicles in the adjacent parts of the street. Each meter shall also be designed and constructed so that upon the expiration of the parking time provided for the denomination of coin deposited it will indicate by automatic operation of a visual signal that the lawful parking period has expired.
('73 Code, § 73.20)