Time has almost run out for churches to replace their wireless microphones as a federal ban on the devices is scheduled to go into effect Saturday.

The new Federal Communications Commission ban includes wireless microphones that operate in the 700 megahertz frequency. Only emergency responders such as police and firefighters will now be allowed to use the frequency.

Currently, approximately 10-12 percent of wireless mics used in churches violate the ban, according to Matt Nodine, chief of staff for the Wireless Telecommunications Bureau of the FCC.

So far, congregations across the country have spent millions to replace to replace the devices.

"I know it has affected several churches that had no plans to change their wireless mics," Rev. Kirk Norman told the Tulsa World. "That's a pretty big hit for any church that wasn't expecting it."

Churches or other facilities using the frequency could face fines and criminal penalties.