VERFAHREN UNTER VERWENDUNG EINES SYSTEMS ZUM AUSTAUSCH VON SCHALTKENNZEICHEN IM VERBINDUNGSVERKEHR IN FERNSPRECHNETZEN, INSBESONDERE IN NEBENSTELLENNETZEN MIT WAEHLUNTERANLAGENVERKEHR

摘要

The method comprises the transmission of main and secondary signals, the address (NK2 to NKn) of the called-back telephone station being essentially transmitted to the main system when a connection is set up between a main system (HA) and a dial-up sub-system (UA) and when a call-back is initiated in the dial-up sub-system, and being stored in a special memory in the main system. 50-Hz AC signals and audio-frequency signals in particular are used as pulse signals. <IMAGE>