An Illinois arbitration Subpoena-Subpoena Ducks Cecum is a legal document issued by an arbitrator in an arbitration case in the state of Illinois. It requires a party to appear before the arbitrator and to bring specified documents and other evidence for review. The Subpoena Ducks Cecum is an important part of the arbitration process and can be used to compel a witness to testify or to gather evidence. There are two types of Illinois arbitration Subpoena-Subpoena Ducks Cecum: a Subpoena Ad Testificandum and a Subpoena Ducks Cecum. A Subpoena Ad Testificandum is served on a person to appear before the arbitrator and provide testimony. A Subpoena Ducks Cecum is served on a person to appear before the arbitrator and bring specified documents or other evidence.