40 ILCS 5/5-213
Service rendered by a policeman, as a regular member of the paid fire department of the city shall be counted, for annuity and benefit purposes as if such service were rendered as a policeman of the city. Any salary so received for service in the fire department shall be considered, for the purposes of this Article, as salary received as a policeman.
Any such fireman who becomes a policeman shall be credited for annuity purposes with an amount equal to the sums deducted from his salary, or contributed by him, and paid into the Firemen's Pension Fund existing in such city by operation of law prior to July 1, 1931, and such credit shall be treated as prior service credits under this Article. Such policeman also has the right to pay to the fund an amount equal to the difference between the amount so credited and the sum he would have accumulated as a policeman from deductions from salary for annuity purposes on the date when such payment is made into this fund, for a period of time corresponding to the period of his service in the fire department subsequent to January 1, 1922, and the city shall contribute concurrently such amounts as are provided by Sections 5-169 and 5-170 of this Article. No credit for service rendered while a member of the fire department shall be allowed, for any of the purposes of this Article, after July 1, 1931, except such periods of service for which contributions were made in accordance with the provisions of the Act relating to the firemen's annuity and benefit fund and for which amounts have been paid into this fund.
Such credits, payments and city contributions shall be improved by interest and be credited on the books of the fund; and when such policeman attains age 57 while in the police service, or becomes separated from service prior to attainment of 57 but after having completed at least 20 years of service, the accumulation then to his credit shall be transferred into the annuity payment reserve and shall thereafter be of the same status as the salary deductions and city contributions provided for by Sections 5-169 and 5-170. Such additional payments and city contributions shall be subject to the refund provisions of this Article.
Any such policeman who was a member of the fire department on the day prior to the effective date shall be considered a present employee in this fund and any policeman who entered the service of the fire department subsequent to that date shall be classed as a future entrant.
40 ILCS 5/5-213