40 ILCS 5/16-168

The board shall meet regularly at least 4 times a year at such time as it may by by-laws provide, or at the call of the president or of a majority of the members. The board may adopt rules for the government of its meetings and for the administration of the system. Each trustee is entitled to 1 vote. The votes of a majority of the members are necessary for a decision by the trustees at any meeting of the board.