Illinois generally follows the more permissive Cali-style model.
The IEEE put out a publication that gives a solid overview of the differences in state laws; it mentions Illinois law specifically in a few places and includes a citation to Illinois statues that you can consult:
The IEEE put out a publication that gives a solid overview of the differences in state laws; it mentions Illinois law specifically in a few places and includes a citation to Illinois statues that you can consult:
http://www.ieeeusa.org/members/IPandtheengineer.pdf