The ATM ABR service category was initially designed to support non-real-time applications, e.g., data file transfer. However it is possible for ABR to support real-time applications (such as distributed multimedia applications) by taking advantage of the inherent traffic control capability of ABR and the adaptation ability of real-time applications. This paper consists of two parts. In the first part we review the principles of operation of the FASTRAC, an ABR control mechanism. This analysis allows us to better understand the adaptation ability of real-time applications, a feature deemed essential to take advantage of the inherent traffic control capability of ABR while guaranteeing a reasonable QoS required by the end application. In the second part of the paper, we explore the use of ABR service to support real-time video transmission using FASTRAC. Our simulation results show that FASTRAC can support both real-time video applications and non real-time applications.