The work in this thesis deals with the design and implementation of a data acquisition and monitoring system that is based on a personal computer using Industry Standard Architecture (ISA) bus. The design of this system involves mainly the hardware circuits, and software. The hardware design and implementation is presented by an interfacing card that is including data acquisition system. It consists of buffering, address decoding, timing stages, and an I/O circuits. The data that need to be processed can be in a digital or an analog form. In the same time the hardware helps to output controlling signals for the testing and controlling of equipments. These signals are in digital or analog form. Similarly, the system software was designed to perform the task of the data acquisition, analyzes, and monitors of data. The system software consists of two parts: control software and Man Machine Interface (MMI) software. The software of the system, is implemented using a visual C++ language; which is the fundamental programming tool for windows. This work used the Microsoft Foundation Classes (MFC) library with the Visual C++, that helps to get the features of the object-oriented programming. The software to be able to perform its task it must have the following sections: communication with external hardware, calculation, real-time data display, data monitoring, operator communication, and event processing sections. All the sections of the system software must work in harmony to achieve the required system task. Finally, the proposed system is simulated as a control system of an electrical substation to evaluate the performance of the system.