Section 5
SEC. 5. All apparatus and appurtenances to be used by the grantee, its successors or assigns, shall be modern and first class in every respect and all telephone lines or installations used, operated and maintained in connection with this franchise by the grantee, its successors or assigns, shall be kept and maintained at all times in a satisfactory manner, so as to render an efficient and adequate telephone service, and it shall be further the duty of said grantee, its successors or assigns, whenever required to do so by the Public Service Commission to modify, improve, and change such telephone system for the electrical transmission of conversations and signals by means of electricity in such manner and to such extent as the progress of science and improvements in the methods of electrical transmission of conversations and signals by means of electricity may make reasonable and proper.