The installer should be able to demonstrate this to you. Once the system has been set up, its controls should be locked to stop unauthorised people from changing them. It is a good idea to note the settings. Ideally, you should use a field strength meter with headphone output to check the system. If the control settings need adjusting, you must use a field strength meter.
Infrared systems use invisible infrared light to carry sound to receivers worn by listeners.
The most widely-used kind of infrared receiver is worn without a hearing aid and a listener only hears the sound that comes from the infrared system. You will need to stock both types of receiver for people who want to use the system, and to keep the batteries in the receivers fully charged. The ear tips must be cleaned or replaced after use. The complete system consists of infrared radiators, a pre-amplifier or mixer unit and a microphone or other audio input source. Radiators are situated to cast infrared light over the listening area, rather like floodlights.