DIGITAL TELEPHONE SET CIRCUIT

摘要

PURPOSE:To attain the unitary power down control to satisfy the prescriptions (less than 380mW in start-up mode and less than 25mW in power down mode) of an I interface in a digital telephone set circuit which receives the power from a feeding station and is connected to the basic interface of an ISDN. CONSTITUTION:The current of a power down control part 16 supplied from a feeding station is limited by a connection or non-connection state detected by a connection detecting part 20. Then a power down control part 13 limits the supplied current based on the detection information of an incoming detecting part 14 and the waiting state set by a mode setting part 11.