40 ILCS 5/14-127
During any period of disability for which nonoccupational, occupational or temporary disability benefits are paid, there shall be credited to the account of the disabled member amounts representing the contributions the member would have made had he or she remained in active employment in the same position and at the rate of compensation in effect at the time disability occurred. Service credit shall also be granted during any such periods of disability for all purposes of this Article except for measuring the duration of nonoccupational and temporary disability benefits. The resolution of a temporary disability benefit into an occupational or nonoccupational disability benefit shall not entitle the disabled member to receive duplicate contribution and service credit under this Section for the period during which the temporary disability benefit was paid.
40 ILCS 5/14-127