What is the difference between FM/DM, Loop, and Infrared assistive listening systems?

Each system varies on its portability, maintenance, ideal settings, components/devices needed, ability to have multiple users on one system, and more. NDC’s Assistive Listening Systems 101 resource provides an overview of each system (See p. 4). This resource also has a comparison tool on the pros and cons of each system and ideal settings where they can be used. We also recommend asking members on the NDC listserv for their experiences with each kind of system and/or vendor recommendations.