80 Ill. Adm. Code 620.310
Definition
Section 620
Section 620.310 Definition
a) Continuous service is the uninterrupted period of service from
the date of original appointment to State service except as provided in Section
620.370.
b) Employees who have accrued continuous service in another merit
system in State service or who have accrued continuous service in State service
not covered by a merit system and who have been transferred to a department
subject to the Code shall be given credit for said service as shall be
determined by the Director or required by law.