METHOD AND ARRANGEMENT FOR SIGNALING THE TRANSMISSION MODE OF A COMMUNICATION SYSTEM

摘要

METHOD AND ARRANGEMENT FOR SIGNALING THE TRANSMISSION MODE OF A COMMUNICATION SYSTEM A communication system signaling method and arrangement utilizing direct current signaling over the line loop connecting a line terminal to a central office. The direct current provides concurrent active/inactive line terminal condition signaling and analog/digital information transmission mode. signaling between the terminal and central office. A current flow in a first direction over the line loop signals the analog mode, while a current flow in the opposite direction signals the digital mode. A change in the operating mode is signalled by blocking current flow at the line terminal. The resulting interruption of current flow is detected at the central office which responds by reversing the direction of current flow over the line loop. Current flow in the line loop indicates the active (off-hook) condition of the line terminal, while the absence of current flow for a predetermined interval indicates the inactive (on-hook) condition.