Verfahren und Vorrichtung zur Impulswahlerkennung bei bestehender Gesprächsverbindung

摘要

The telephone dial may only be used today to reliably remote control terminals connected by a telephone line by means of systems with selection tones or separate tone generators. The invention allows terminals with pulse selection mode to be used for remote controlling other terminals connected thereto by a telephone line in spite of the modification of the signals, for example filtering of the selection pulses, by connected switching centres. The disclosed process and device allow terminals to be remote controlled from any kind of telephone set to which they may be connected. The terminal that is to be remote controlled sends out a test signal to determine the mode of transmission of the connection between both terminals. The test signal is reflected by the termination set of the controlling terminal. The mode of transmission is analysed by comparison with typical transmission properties that may be predetermined or determined for the existing connection, in order to detect the occurrence of selection pulses sent by the controlling terminal. The occurrence and the number of coherent selection pulses may thus be reliably determined even when the selection pulses are strongly modified.