Ring-Back Procedure For An FDM Telephone System
Original Publication Date: 1979-Sep-01
Included in the Prior Art Database: 2005-Feb-20
In FDM (frequency division multiplexing) switching systems, RF bandwidth on a coaxial cable is divided into a number of channels which are identified by frequency bands. Switching is accomplished by selecting or changing the frequency of the transmitters and receivers on the cable. In a multiple communication terminal system, such as an analog voice or PBX system, frequency channel assignment and operation are supervised by a programmed central controlling unit. The central controlling unit communicates with the terminals along the coaxial cable and directs their operation by a signaling channel. Each terminal contains both a signaling and a conversational receiver.