Abstract: A method for receiving-end automatic identification of quadrature amplitude modulation (QAM) mode (16-, 64-, 256-QAM; 32-, 128-QAM) of a received signal. The mode having been transmitted in accordance with QAM modulation, in which the received signal is demodulated with symbol values I-Sym and Q-Sym of different significance being obtained. In order to configure this identification process such that it is reliable and can be realized by relatively simple circuit, the invention provides for the significance of the symbol values I_Sym and Q_Sym to be acquired, and for the symbol values I_Sym and Q_Sym to be added in accordance with their significance in order to obtain a statistical distribution of maxima as a representative of the transmitted QAM mode.

Abstract: An electronic auxiliary contact for a contactor has at least one switch element controllable to the conducting and non-conducting states for the purpose of indicating the position of the contact bridging member in the contactor, and a switch-activating element mechanically connected to the contact bridging member and capable of activating the switch element. The switch-activating element incorporates at least one activating element, and the switch-activating element makes no mechanical contact with the switch element. The system provides a reliable method of monitoring the operation of a contactor.