Voltage and current controlled converter for telephone ringing

Abstract

A single channel carrier system for telephone service is disclosed including a remote terminal having a ringing generator included therein for generating ringing signals to operate the ringers of remote subscribers. The ringing generator is a dc-to-dc converter for stepping up a battery voltage to ringing voltage lvel that is interrupted at a 20 Hz rate. The generation of ringing signals is controlled by a carrier signal interrupted at a ringing rate. Detection of the ringing signals on the carrier utilizes a delay circuit to prevent response to inadvertent signals as well as delay hysteresis to ensure the bridging of detection from one 20 Hz cycle to the next. The ringing generator must also be regulated, both in current and in voltage, to prevent danger to personnel, damage to equipment, and excessive power consumption.

Dependencies are inferred from the claim text.