A process is provided for transmitting a signal, without material connection, through a conducting wall which may be a ship's hull, to external user apparatus. A current supplied by a generator and whose intensity is proportional to the amplitude of the signal to be transmitted is applied between two points on the hull. The magnetic field variations generated by the passage of the current are detected by a sensor on the other side of the hull and, suitably amplified, are used for controlling an apparatus.

Disclosed in an induction range having a counter with an uninterrupted top or working surface on which a cooking vessel is supported and inductively heated by an induction coil situated beneath the counter. Since only the cooking vessel is inductively heated, rather than the counter, the counter is relatively cool. In order to actually determine the temperature of foodstuff being cooked in the vessel there is provided a temperature sensing unit suitably encapsulated in an immersion-type thermistor unit to which there is attached flexible cable comprising thermistor leads or conductors. The thermistor unit is immersed in the foodstuff in the vessel. The flexible cable extends out of the cooking vessel and is terminated in a portable magnetic coupling device which, when resting on the work surface of the range counter, magnetically couples signals representing temperature correlated changes in the thermistor unit's impedance to a magnetic receptor device mounted below the range counter. Thus, temperature changes in the immersed thermistor unit are reflected as temperature correlated impedance changes to the magnetic receptor device and these impedance changes, in turn, are effective to help determine the true temperature of the foodstuff being cooked in the vessel.

A device for fixing ear-phones and/or mini-microphones, especially to items of clothing or equipment. The aim of the invention is to develop a secure, easy to handle, precisely positionable, economical, optional means of fixing even earphones and/or mini-microphones whose structural shapes are years old. The fixing means should neither increase the transport weight nor the construction volume of the earphones and/or mini-microphones, should be usable even in an adapted state in a appropriate position on the item of clothing and/or equipment, and should guarantee (with the exception of special structural shapes) overload protection with an emergency triggering function when there is a strong pull on the earphone and/or microphone cable. To this end, a permanent magnet, a magnet system or an adhesive system is provided at the designated fixing point for the earphones and/or mini-microphones outside or inside of the particular item of clothing and/or equipment.

An inductive coupling permits bi-directional data and power to be transferred through the skin of an aircraft thereby avoiding pin connectors. The coupling comprises a sending unit which is detachably mounted to the skin exterior, and the pick-up unit is located on the interior skin surface in alignment with the sending unit.