Abstract: An intelligent alarm apparatus with a telephone network interface. The alarm apparatus includes an alarm sensor, which is directly connected at a high impedance level through an integrator and a detector to the alarm signal input of a programmable processor. The processor is in a power-saving standby mode until an alarm signal is received. Once an alarm signal is received at the processor, an output signal is transmitted to the designation programmed in the processor. A power supply section of the alarm apparatus is connected to a telephone line from which the alarm apparatus obtains its power feed.

Abstract: The invention concerns a transmission system for telephone communications comprising at least two telephone sets, each incorporating a microphone and a receiver and/or loudspeaker, and a telephone line connecting the telephone sets by at least two conductors in order to form a current loop.