Abstract: Instead of the method of performing the power disconnection in the existing phase angle control AC power line communication, using relays or various power semiconductor devices, if communication is executed through data mapping on a pattern where polarity switching (in the case of AC, phase-shifting by 180°) occurs at a differential voltage level of a power line, no power disconnection occurs and high voltage interval is utilized so that the power line communication is strongly resistant to external noise and provides high communication speed, while transmitting several bits in one period of AC voltage waveform. This solves the disadvantages the existing classical condenser coupling type power line communication and the phase angle control AC power line communication for long distance have had. Even though the power line communication is utilized for DC power line communication, many advantages are obtained and high power transmission efficiency is achieved through the relays.

Abstract: The present invention relates to a device for displaying floor information of an operating elevator, which provides a user with information on the floor where an elevator car is positioned by operating the current position of the elevator car. The device is not electrically connected to an existing elevator driving system, so that the installation procedure of the display device is simple and easy. In addition, it is possible to realize integration even though every elevator employs protocols different from each other.