Within one hundred eighty days after the commencement of construction and installation of the cable communications system, grantee shall proceed to render service to subscribers, and the completion of the installation and construction shall be pursued with reasonable diligence thereafter, so that service to all of the areas designated and scheduled on the map and plan on construction made part of the franchise ordinance or agreement between grantor and grantee granting a franchise shall be provided as set forth therein. Grantee is required to complete construction of the entire city in a maximum of three years, although a shorter time may be specified in the franchise ordinance or agreement between grantor and grantee granting a franchise. (Ord. No. 1097, § 1 (part).)