The director shall, as soon as practicable after this article takes effect, ascertain and record the duties of each position in the state service and, after consultation with appointing authorities and principal supervising officials, recommend to the board a classification plan, together with proposed rules for its administration. Such classification plan shall show each class of position in the state service and, when approved by the board, shall be made public together with the rules for its administration. Each such class shall include positions requiring duties which are substantially similar in respect to the authority, responsibility and character of the work required in the performance thereof and shall be designated by a title indicative of such duties. Each class shall be so defined that the same requirements as to education, experience, capacity, knowledge and skill are demanded of incumbents for the proper performance of their duties, that the same tests of fitness may be used in choosing qualified appointees and that the same schedule of pay can be made to apply with equity under like working conditions. The class titles shall be used in personnel, budget and financial records and communications. As far as practicable the natural or probable lines of promotion to and from the class of position shall be designated or indicated.