Controller for a Remote Line Concentrator in a Time-Separation Switching Experiment

An earlier paper 1 has described the general organization of an experiment in time-separation switching. Two principal functional parts were incorporated into this experiment: a line concentrator, which might be remote from a central switching office, and a concentrator controller, which would be located within the central office. In this paper we will describe in greater detail the organization and design of the concentrator controller. A companion paper 2 presents details of the remote line concentrator. In both papers it will be assumed that the reader is generally familiar with Ref. 1. The experimental equipment provides 24 time-division channels between the remote concentrator and the controller. Since the controller would be located at a central switching point, it would be more accessible for maintenance than the concentrator; therefore, whenever there was a choice between locating equipment in the concentrator or in the controller, the controller was chosen. Of the 24 time-division channels, which will be referred to as time slots, the first 23, numbered 0 through 22, are used for pulse-code-modulated speech. Time slot 23 is reserved for scanning and control functions, which will be described in the body of this paper. Each time slot recurs at an 8-kc rate, and each contains eight binary digits; the first seven are 59