Abstract: A system for providing DC power on local telephone lines, such as telephone lines in a building or office, for powering devices and circuitry associated with communications over those telephone lines, as well as other functions. Desired voltage and power levels are supplied over local telephone lines by separating the DC power component from the central office or private branch exchange with a DC blocking filter while passing all AC telephony signals. A distinct DC power is then imposed over the telephone line for powering both the telephony service as well as other loads. Conventional telephone off-hook detection is simulated for compatibility with the central office or private branch exchange. The functions required may be integrated, partially or fully within a telephone outlet.

Abstract: An electronic step-by-step switching system utilizes much of the equipment now present in conventional electromechanical step-by-step telephone exchange switches. Conventional line finders, selectors and connectors are modified by removing the relay logic and replacing it with microprocessor based controllers. The modified line finders communicate through a bus with an originating controller and the modified connectors communicate through a bus to a terminating controller. The controllers are interconnected for data exchange through high speed buses that are supervised by a bus controller. A programmer station is installed for bi-directional communication through the bus controller. The originating and terminating controllers include memory storage for maintaining status information concerning the subscriber lines within the groups of corresponding line finders and connectors. The modified line finder works in conjunction with the originating controller to identify the line for an off-hook subscriber.