Section 5
SEC. 5. All apparatus and appurtenances used by the grantees, their successors or assigns, shall be modern and first class in every respect, and all telephone lanes or installations used, maintained and operated in connection with this franchise by the grantees, their 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 the further duty of said grantees, their 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 method of electrical transmission of conversations and signals by means of electricity may make reasonable and proper.