This paper describes error probability of the second-ordered BAM in the presence of noise bits in initial input. A calculation method is proposed to estimate the error probability at the second iteration to retrieve a library pair. Theoretical estimation suggests that the BAM with a larger number of neurons are more robust for the noise bits: the error probability of 10/sup -6/ is obtained for the BAM with 500 neurons in a layer even the initial input has 90 noise bits (15% of numbers of neurons). Dependence of number of library pairs on number of neuron is estimated for the various error probabilities by assuming 15% noise bits. If the error rate of 10/sup -6/ is permitted, capacity of the BAM can be increase by about 40%.

To improve the ratio of successful calls, a new switching system permitting callers to store messages when the called party is busy or does not answer can be constructed by adding a message storing function to the conventional circuit switching system. The mutual traffic influences exerted by this combination of circuit and message switching systems have not yet been clarified. This paper considers a two-stage loss system traffic model consisting of a circuit switching system that has a message switching system connected to it. The traffic characteristics of this model are analyzed using the nonindependent state transition probability, which depends upon the interacting states of the circuit and message switching system. A method of solving the state equations by determining the state transition probabilities of the message switching system from the state probabilities of the circuit switching system is proposed. Using this method, the mutual traffic influence of the circuit and message switching systems is evaluated.

In tomorrow's automated offices, an important role will be played by voice storage systems which enable telephone communication at any time. This paper discusses the problems and technical consideration in designing a flexible voice storage system featuring a distributed structure whose capacity can be expanded at will. Recent advances in microprocessors and magnetic minidisk devices have made this kind of system economically feasible. An efficient new method for real-time accessing of distributed files is proposed which guarantees continuous storing and forwarding of voice messages. A simple method of estimating the required file capacity is also given on the basis of a voice message traffic analysis.

This paper outlines the features of a new integrated switching system for voice and data. It is composed of integrated subscriber terminals, integrated subscriber lines, an integrated digital switching system, and integrated storage facilities. This paper shows that the introduction of the integrated storage facility can create various new service utilities and improve the traffic capacity of the system.

A new subscriber communication system and its design philosophy are described. In addition to telephone communication, the system is simultaneously able to offer data communication, still picture communication, etc. The system is composed of a packetized voice/data terminal, a multi-service switching equipment and the digital subscriber loop connecting between them. The system utilizes the existing subscriber line efficiently and is entirely suitable for coming telephone and data public digital network. 64 kbit/s PCM coded voice conversation and 48 kbit/s data communication were achieved simultaneously over 96 kbit/s digital subscriber line which was spanned up to 2 km.