Some of the factors stimulating the use of asynchronous transfer mode (ATM) are discussed. The objective of extending the flexibility and features that ATM provides from the switching and interoffice network to the local access network to reach the residential and small-business customers is discussed. How the ATM technique could be applied to fiber-in-the-loop (FITL) systems to meet this objective is considered.>

This paper describes a working research prototype of an ISDN central office which demonstrates the key hardware and software elements needed for ISDN services. As such, it does not include all the normal trappings of a central office such as maintenance or non-ISDN interfaces and there is no attempt to cope with heavy traffic conditions. Details are included on the prototype central office architecture which is a distributed system, the call processing procedure's and the necessary data structures which provide basic circuit switching and a small number of advanced capabilities. These include the ability to suspend and resume calls at different line appearances, the ability of users to set their own line restrictions and move their services from one line to another, and the allowance of multiple directory number listings for terminals. Also discussed are security aspects of such line controls and commonplace call scenarios which must be considered to avoid deadlocks or incorrect processing by the call processor. Detailed presentations consider all of these aspects within the context of a real-time distributed central office software architecture.

Cellular spaces are shown to possess properties favorable to reconfiguration. As a first step in the direction of reconfigurable cellular spaces, this paper demonstrates the implementation of arbitrary finite-state machines in self-diagnosing cellular spaces. The results cover single cell failures caused by erroneous state transitions or by erroneous outputs. One of the attractive features of the implementation is the absence of any hard core components. As an intermediate step, it is shown how to transform any given cellular space into a self-diagnosing cellular space. The results demonstrate that the control structure (which is a finite-state machine) of any computing device can be implemented as a self-diagnosing entity without hard core.