US 4,063,037 A · Telephone metering interface with reverse signal sensor

Abstract

A sensing circuit is placed in the tip line of a subscriber's loop to sense, selectively, the placement of an outgoing, local call. The circuit includes a first LED for energizing a metering circuit upon detection of a billable call, and a second LED for latching the metering circuit in its energized condition within a predetermined interval after the billable call is detected. The metering circuit is automatically deenergized when the called party goes on-hook. A balancing circuit is included in the ring line of the equipment to balance the impedance created in the tip line by the sensing circuit; and the metering circuit can be designed selectively to produce a one-shot metering pulse for each billable call, or to produce a continuous signal for the duration of the call.

Claims14

Dependent claims

In combination with a telephone having tip and ring lines the polarities of which are reversed upon each successful placement of an outgoing call, message metering interface apparatus, comprising

means connected in circuit with said lines for detecting when an outgoing call from the telephone has been successfully completed,
said detecting means including means generating a first signal when the current flow in one of said lines flows in a predetermined direction,
second signal generating means including signal sensing means optically coupled to said first signal generating means and operative upon sensing said first signal to generate a second signal, and
means responsive to the generation of said second signal to generate a third signal for actuating a message metering device associated with the telephone.

1 more element

Dependencies are inferred from the claim text.

Telephone metering interface with reverse signal sensor

Life of this patent

Telephone metering interface with reverse signal sensor

Life of this patent

Abstract

Claims14