Mich. Comp. Laws § 205.94q

Sec. 4q. (1) The tax levied under this act does not apply to the purchase of machinery and equipment for use or consumption in the rendition of any combination of services, the use or consumption of which is taxable under section 3a(1)(a) or (c) or 3b except that this exemption is limited to the tangible personal property located on the premises of the subscriber and to central office equipment or wireless equipment, directly used or consumed in transmitting, receiving, or switching, or in the monitoring of switching of a 2-way interactive communication. As used in this subsection, central office equipment or wireless equipment does not include distribution equipment including cable or wire facilities. (2) Beginning April 1, 1999, the property under subsection (1) is exempt only to the extent that the property is used for the exempt purposes stated in this section. There is an irrebuttable presumption that 90% of total use is for exempt purposes.