Supply voltage setting system for communications subscriber circuit - uses detected loop circuit resistance upon initial connection of subscriber circuit to 2=wire subscriber line

摘要

The supply voltage setting system responds to a recognition signal indicating a loop connection of the subscriber circuit, for setting the supply voltage in dependence on the loop resistance. This voltage is held constant until termination of the loop connection. Pref the loop resistance is determined from the measured voltage across the subscriber lines. The supply voltage is set to a value corresp. to the sum of the latter voltage and the min. voltage required for operation of the supply current sources. USE/ADVANTAGE - For subscriber circuit connected to 2-wire subscriber line. Eliminates need for continuous supply voltage regulation. Lower loss without appearance of additional noise.