The PD98409 (NEASCOT-S40CTM) is a high-performance SAR chip for segmentation and reassembly of ATM cells. Provided with a PCI (Peripheral Component Interconnect) bus interface control memory and supporting a MPEG packet transfer engine function to mitigate the workload of the CPU in transferring compressed image data, this chip has ideal specifications for use in a set top box (STB) to interface with an ATM network. The PD98409 conforms to ATM Forum recommendations and has AAL5-SAR sublayer and ATM layer functions.