EINRICHTUNG AN EINEM FERNSPRECH-TEILNEHMERANSCHLUSS MIT ZWEI WECHSELWEISE AUTOMATISCH ANSCHALTBAREN SPRECHSTELLEN ZUR ABSCHALTUNG EINER, EINEN UNGEWOLLTEN SCHLEIFENSCHLUSS AUFWEISENDEN SPRECHSTELLE VON DER VERMITTLUNGSSTELLE AUS.

摘要

The circuit has a pair of extensions which are coupled to the telephone line via a change-over switch (U-S1-S2) for preventing an unwanted loop circuit between the two extensions. The change-over switch (U-S1-S2) has a controlcircuit (9) which is permanently coupled in parallel with the telephone line (0,60) and responds to an AC signal of given frequency for operating the switch (U-S1-S2). A monitoring device provides a resetting signal for the switch (U-S1-S2) and the short circuit detector continuously monitors the line voltage.