| 摘要 |
PURPOSE:To reduce the current consumption and the generated heat and to make the power supply installation small with respect to the subscriber circuit in which a maximum talking current is limited without giving effect onto talking quality and supplying the result to a terminal equipment in a digital exchange or other without giving effect onto the talking quality. CONSTITUTION:A subscriber circuit SLICA1 supplies a feeding current from a constant voltage constant resistor feeding circuit BFR to a terminal equipment TER via a current detection circuit IDET and a variable pseudo line CPL. A control circuit ICNT compares a detection output IDETO of the circuit IDET with a reference current signal IRF and sets a control signal CPLC so as to increase the length of the line CPL and to decrease the feeding current when the detection output IDETO is larger than a reference current signal IRF. The operation is implemented till the detection output IDETO of the circuit IDET and the reference current signal IRF are equal. Furthermore, the control circuit ICNT sets the control signal CPLC so that a pseudo line length of the line CPL is '0' when a line terminal resistance RLT is large and the feeding current is smaller than the reference current signal IRF. |
