Conn. Gen. Stat. § 5-176
A member with permanent status who was previously employed in the public schools of this state and who was a member of the Teachers' Retirement Association, may receive credit for retirement purposes for all such service for which he paid assessments. Such member shall make retirement contributions equal to five per cent of salaries received for such service, with interest thereon at the rate of five per cent per year from September 1, 1917, or from the date of such employment thereafter, to the date of payment. If the member was in state service on or before June 30, 1967, such payment shall be made before June 30, 1971. If the member entered or reentered state service on or after July 1, 1967, such payment shall be made within five years from the date of employment or reemployment as a state employee with permanent status. No such member shall be eligible for retirement credit under this section until he has completed ten years of state service and, in the event of his retirement while ineligible for credit under this section, all contributions and interest thereon paid by him under this section shall be refunded. Notwithstanding the provisions of this section, any member with permanent status who was employed in the public schools of this state before July 1, 1980, shall receive retirement credit for his or her period of membership in said teacher's retirement system upon payment of contributions equal to five per cent of his or her salary for such period plus an amount actuarially determined by the Retirement Commission as necessary to fund the increase in benefits payable by reason of such receipt of retirement credit by June 30, 1981.
Conn. Gen. Stat. § 5-176
(1959, P.A. 441; 1961, P.A. 234, S. 25; February, 1965, P.A. 343, S. 1; 1967, P.A. 648; 731; 1969, P.A. 345; P.A. 80-407, S. 3, 4.)