Abstract: An interface system for installation in a centralized location remote from the customer's premises. A single line is employed in normal operation between the customer's telephone equipment and certain special use equipment such as a centrally located answering and recording equipment. The equipment may be located in a telephone central office or alternately in a separate location remote to both the customer's equipment and the telephone central office. When the equipment is in operation, the customer's phone is isolated from the telephone central office. If the customer goes "off-hook" the equipment is dropped and the customer's line is automatically connected to the incoming call.

Abstract: A digital intercept recorder/announcer system for use in conjunction with a telephone central office. The system performs the function of recorded message announcement for messages such as wrong number, time or weather announcements. The system samples and digitizes audio input signals from local or remote audio sources. Sampled data is stored in sequential fashion in memory so that it may be read out of memory exactly as it was stored. Upon demand, these stored signals are retrieved from memory, reconverted to an analog form and coupled to a subscriber's line for audio transmission to the subscriber. Delta modulation techniques are employed in the system.