As a result of recent increases in demand for network bandwidth, it is becoming more important that high-speed telecommunication networks be installed, managed, and used as efficiently as possible. In order for these objectives to be realized, it is essential that network operation be studied and accurate models of its behavior developed. Unfortunately, the data acquired from testing with network equipment is often less than ideal due to the cost and capabilit es of test equipment currently available commercially. Testing suffers as a result of the equipments high cost, inability to generate network traffic with certain types of properties, and the limited amount of traffic which can be recorded for analysis. A network interface card designed specifically to overcome the limitations of commercial test equipment is one solution for improving the results of current network testing. This card would not duplicate all of the capabilities of existing test equipment. Instead, it would only strive to improve the traffic generation capabilities to allow all possible types of network traffic sources to be simulated, extend network traffic capture periods to provide a sufficient amount of data for analysis, and be built at a low-enough cost to be a viable alternative to commercial equipment. This thesis will describe the development of a card designed for generating and capturing ATM network traffic at OC-3 rates.