Function monitor for telephone network - with country satellite exchanges using capacitors to operate alarm

摘要

The function monitor, for a telephone network with country satellite exchanges (i.e. small unmanned rural exchanges), has each both-way finding selector provided with a monitoring circuit containing capacitors charged from the supply voltage over resistors. Trigger transistors are connected by their bases to the capacitors and are turned on when the capacitors' voltage reaches their thresholds. When this happens, the transistors operate a failure alarm and the capacitor are discharged. The monitor releases the alarm if after one or two cycles the finding process has brought no results -- this release is subject to the condition that when alll main lines are busy no result can occur even though no failure is present.