Michigan Compiled Laws, Chapter 484. Telephone, Telegraph and Radio § 484.1203

Sec. 203. The digits 9-1-1 shall be the primary emergency 9-1-1 number within every 9-1-1 system established pursuant to this act. A public safety agency whose services are available through a 9-1-1 system implemented under this act may maintain a separate secondary backup number for emergencies, and shall maintain a separate number for nonemergency contacts.