Telex signalling and distortion analyser

Abstract

The scope of the project was to develop the working prototype of a microprocessor - based unit which could be used for diagnostic testing on trunk and line circuits in a telex exchange. By incorporating particular features in both hardware and software design, it has been possible to integrate the prototype system within the existing exchange maintenance set-up, allowing remote access of test facilities through a simple, interactive mode of operation. In particular, the distortion facility of the Telex Analyser may be viewed as a contribution to the study of telegraph distortion through the development of an automatic distortion analysis algorithm, the dedicated logic of conventional measurement equipment being replaced by general purpose microprocessor peripheral hardware. The introductory chapters of this thesis outline the principles underlyinq the operation of the international telex service, based upon a circuit - switched public telecommunication network. The treatment of telegraph multiplex systems provides the theoretical basis for the distinction between regenerative and non-regenerative transmission media. [...]