VOICE SWITCH CIRCUIT

摘要

PURPOSE:To improve the talking quality of a conference calling system using two public telephone circuits by measuring the transmission loss of the circuit set between aural conference equipments and reducing the insertion loss of a voice switch based on the measurement value of said transmission loss. CONSTITUTION:The transmission loss values of two circuits of an aural conference equipment storing two analog telephone circuits are measured by a transmission loss measuring signal generating/level measuring circuit 71. Then the circuit 71 sends the result of measurement to a switch loss control circuit 33. The circuit 33 subtracts the received transmission loss value from the set sound volume control value and applies the obtained final insertion loss value to a voice switch insertion loss circuit 31 or 32.