N.J. Stat. § 18A:66-105
Persons employed by any such board of education on March 25, 1935 and also on April 29, 1946, who took advantage of the provisions hereof by making application to the board of trustees on or before April 1, 1948, and paying into the fund, with and at the time of such application, such percentage of his salary as provided for in subsections a. and b. of section 18A:66-107, for the period of his employment beginning with the date of the incorporation of such pension association or the date of his employment by said board, whichever is the later date, together with interest at 3% per annum or such other legal rate as shall be determined, from time to time, by the board of trustees; and after such application and payment have been made by the employee the board of education by which the person is employed shall pay into the fund, if it has not already done so, 4% of the employee's salary for the period of his employment beginning with the date of the incorporation of such pension association or the date of the employment of said person by said board of education, whichever is the later date. All persons coming into the employ of any such board as permanent employees subsequent to March 25, 1935, shall become members of such pension fund at the date of said employment or appointment and any such employee shall be required to pay into such fund such percentage of his salary as provided for in subsections a. and b. of section 18A:66-107.
N.J.S. § 18A:66-105