AUDIO FREQUENCY INDUCTION LOOP SYSTEMS

AFILS give direct listening at meetings/conferences for the hard of hearing. It is becoming more common that this system is provided for fully monitored emergency use, initialising evacuation warnings.

Single phase and split phase systems produce coverage evenly over the intended area.

Privacy from meetings can be designed into the systems with attention to security and importance of limiting transmission.

Most hearing aids nowadays have a switch marked M and T. Some even have M, MT and T. The M (microphone) position is for 'normal' listening, that is receiving airborne sound via the microphone built in to the hearing aid. The T (telecoil) position is for receiving the sound via an induction coil which is built in to the hearing aid. For the induction coil to provide sound, a magnetic field is needed via which the sound is transmitted. It was intended to make it easier for the hearing aid user to hear over the telephone, by picking up the sound via the magnetic field generated by the diaphragm coil in the receiver of the telephone. Induction loop systems are provided in public places such as churches, cinemas and theatres, and even in the home, and the T facility is used in such cases to listen inductively, without the interference of airborne background sound. The MT position which is provided on some hearing aids allows listening simultaneously both to airborne sound via the microphone and to inductively transmitted sound via the telecoil.

Social, welfare and public health authorities have also become increasingly aware of the need for induction loops in sheltered and residential accommodation. Section M of the UK building Regulations also specifies the need for such systems.