It is well known that when an alternating current is passed through a wire, a magnetic field is generated around the wire. If a second wire is brought within this magnetic field, a corresponding alternating current is created within the second wire. In technical terms it is said that the current is induced in the second wire. To the technically aware this is common knowledge but not all hearing aid users are so aware, indeed many are unaware of such things, and do not have any idea of the great help an induction loop can be to them in compensating for their disability. Most hearing aids nowadays have a switch marked M and T. The M (microphone) position is for normal listening, that is receiving airborne sound via the microphone built into the hearing aid. The T (telecoil) position is for receiving sound via an induction coil, which is also built into the hearing aid. This was originally intended for use with a telephone by picking up sound via the diaphragm coil in the receiver. With the installation of induction loops now being provided within public buildings the T facility is used in these locations to listen inductively without the interference of airborne background sound. Some hearing aids have an MT position, which allows simultaneous listening to both airborne and transmitted sound.

A hearing aid induction loop consists of an amplifier and a loop. The amplifier is connected to a sound source, which is then transmitted in the form of an alternating current via the loop. A simple loop consists of an insulated wire, one turn of which is placed around the perimeter of a room. When the alternating current from the amplifier flows through the loop, a magnetic field is created within the room. If a hearing aid user switches his hearing aid to the T position, the telecoil in the aid picks up the fluctuations in the magnetic field and converts them back to an alternating current. These are in turn amplified and converted by the hearing aid into sound thereby allowing the person with the hearing aid to move around the room freely and receive the sound at a good comfortable level.

The general environment is becoming noisier and in many instances we all find it difficult to understand what is being said to us. For a person with impaired hearing wearing a hearing aid the situation can become impossible for them to hear and understand. It is for these reasons that more attention is now being given to assisting hearing aid users by installing induction loops in the work place, in schools, banks, churches and other public places.
When customers with a hearing aid enter a bank, post office, and building society or other public building, they are faced with the problem of background noise and many people talking at the same time, thus making communication difficult.

When a hearing aid user and potential customer or existing client enters a public building such as a bank a local induction loop will be of great assistance when talking to his or her account manager. A counter or desk communication system would be advantageous in this situation. This type of device would consist of a mini microphone discreetly placed within the account manager's desk along with an amplifier and a loop pad. A local 240volt electrical supply is required to power the unit, which can also be installed by the installation engineer. These types of units have a one/two metre range enabling you to keep the conversations private yet give the customers an improved quality service and improved hearing. Larger loops can be installed in meeting and or conference rooms and consideration will need to be given in order to avoid "spill over" where discretion is required. This is generally avoided by the use of a multi loop array specifically designed for the application. This would typically be catered for at the design stage of the project and incorporated within the works during construction or refurbishment.