DEVICE FOR DETECTING TELEPHONE LINE SEIZURE, AND APPARATUS COMPRISING MEANS FOR PERFORMING A TELEPHONE LINE SEIZURE

摘要

Device for detecting occupancy is 1 second telephone line connected in series to the telephone line and can be placed in the American and a second optical coupler (OC ₁ , OC ₂ ) perform the measurement of the voltage across the telephone line (U _L ). A first optical coupler (OC ₁ ) may be to discharge the capacitor (C) connected to the telephone line , the second optocoupler (OC ₂ ) is the discharge current (I _D ) the image currents (I _{in the measurement circuit (S) D is converted to} '). The device includes a first optical coupler (OC ₁ ) to the means of ensuring the negative feedback from the second optical coupler (OC ₂ ). With this arrangement , the influence of the transfer coefficient for the voltage measurement optical coupler , to improve the accuracy of the measurement is reduced .