Abstract: An arrangement is described for testing a communication path to a 2-wire analog line through a time-division multiplexed switching system, wherein each analog line is coupled to the system by a hybrid circuit which provide separate transmit and receive paths. A digital tone source is coupled to a time-division bus of the system such that the digital tone source transmits signals toward the line on the receive path. A ring relay associated with the line is operated to produce an open circuit condition between the hybrid circuit and the line. The open circuit alters the transhybrid loss of the hybrid circuit such that the signals on the receive path are reflected back toward the time-division bus on the transmit path. A digital tone detector is coupled to the transmit path such that the reflected signals may be detected.

Abstract: A telecommunications system which is capable of implementation in many configurations. The simplest and smallest configuration is that of a single processor-controlled module or unit using time division switching. Within a module, a processor and its attendant memory provide program memory and control the functioning of an automatic scanner driver, the automatic scanner driver interfacing between the processor and the system terminal circuits. In addition the automatic scanner driver has capability of storing temporary information during call processing through a time division switching network. For configuring larger systems, plural modular units are combined, the units being combined with control elements common to the system such as a control processor, including memory and a processor to module interface and module to module interface. The common elements act to control the feeding of information between modules.