Bajic, Vladimir B.Galbraith, Bruce G.Crankshaw, Brett Robert2017-11-152017-11-151994DIT26054http://hdl.handle.net/10321/2851Submitted in compliance with the requirements for the Masters Diploma in Technology: Electrical Engineering (Light Current), Technikon Natal, Durban, South Africa, 1994.One of the telecommunication facilities provided by Telkom S.A. is connection to the National and International X.25 data network. This network follows the international data protocol standard based upon the CCITT Recommendation X.25. The network allows data calls to be made from the X.25 user in very much the same fashion as a caller on the Public Switched Telephone Network (PSTN), in that the caller must specify the number of the called user on the network in order to be connected. It is in this environment, specifically in the testing and maintaining of these data circuits, that this study is based.193penThesishttps://doi.org/10.51415/10321/2851