Composer, Author and Publisher. This 9-digit number is used to uniquely identify a songwriter or publisher. CAE numbers are also referred to as IPI (Interested Parties Information) numbers. The CAE system was replaced by the IPI system, the new industry standard, in 2001, but the two are often used interchangeably. Rightsholders are assigned CAE/IPI numbers when they are granted membership to a PRO. You can find the CAE/IPI of an affiliated songwriter or publisher by performing a repertory search at ASCAP or BMI. Your CAE number is not the same as your ASCAP member ID or BMI account number.