This paper assesses a model of voice / data integration on statistical time divsion multiplexing technique. A comparison between fixed and movable boundary frame structure is introduced and the selection of a movable boundary than fixed boundary _due to the efficient sharing of voice and data transmission capacity in the frame period with higher channel utilization_ is discussed. Hybrid switching system which combined circuit and packet switching techniques is provided in this model, where the hybrid switching frame period consists of both circuit switched voice traffic and packet switched data traffic The performance of the model is evaluated and the results obtained are analyized , also the blocking probability of voice source and the waiting delay of data packet are measured . The effect of number of slots( N 1,N 2 ) assigned to voice / data sources on the system performance is evaluated. The effect of the offerd voice load on the waiting delay of data packets for the propose' integration model is also provided