We study a queueing model consisting of two units 1 and 2 connected in series with a finite intermediate waiting room. The customers in the buffer are served according to a general bulk service rule with exponential times. Unit 2 is in the up state for a random interval of time following an exponential distribution with parameter α and the distribution of time spent in the down state is exponential with parameter β. Here we obtain the steady state probability vector for the number of customers in the queue.