What happens when you get a DUI in one state but are licensed in another?

So here is what I think that you are saying.  That you are licensed to drive a car in BOTH California and Illinois? Is that correct?  Technically speaking you are not permitted to be licensed in two states at one time so I think what you face is not suspension of the Illinois license for the DUI conviction but because of the issue of dual licensing.  If I am incorrect in my understanding of your question please write back.  But if you are licensed only in Illinois but convicted and suspended in California, you must also comply with the Illinois laws on the issue.  One major pitfall for persons who get a DUI conviction in one state while being licensed in another is FAILURE to comply with BOTH states' rules for license reinstatement.  If both states' regulations are not met, the driver WILL BE BARRED in the state that non-compliance has occurred.  If caught driving in THAT state --- even with a plastic license from another state --- will lead to arrest for driving while suspended (or driving while revoked).