X.PC

Abstract: A location independent personal telecommunications system is presented that utilizes an out-of-band bi-directional burst data communications network to assist in the routing of personal communications via an in-band voice and data communications network. Access to the out-of-band network for communication is regulated by a multiple access communications protocol. Each user is synchronized with the other users of the network to the protocol and will access the network only during certain time periods that are reserved by the protocol for message traffic between network users. A collision avoidance scheme is included in the protocol to resolve instances of simultaneous transmission of message traffic by multiple users during the same time period.

Abstract: The past few years have seen many applications of the mini-computer in digital communications. They have been used as interfaces to larger computers. They have been used as terminal drivers and data multiplexors. They have been used to connect computer centers for intercomputer communication. TYMNET* is a communication net that encompasses all of these features at relatively low cost.

Abstract: The design of a computer communications device is presented the purpose of which is to act as a translator between two virtual circuit protocols: Tymnet's X.PC, and the US Department of Defense's DOD's TCP. Protocol translation in general and details on how the X.PC/TCP translation is done are discussed. Problems found in the task of protocol translation are also discussed. >

Abstract: Telecommunications systems embody means for establishing communications links between entities within that telecommunications system. These links are usually established following an exchange of digital messages in accordance with a communications protocol. Communications protocols are often sophisticated, involving a sequence of complex message exchanges. Known protocol analysers for testing communications protocols involve the use of data bases, which are pre-programmed with all possible combinations of messages sequences which correspond with the protocol to be tested. This is time consuming, expensive and inflexible. By using a neural network within the protocol analyser, a sequence of messages exchanged in accordance with a correctly operating communications protocol may be learned, obviating the need for a data base.