There are two components in the Intel APIC system, the "local APIC" (LAPIC) and the "I/O APIC". There is one LAPIC in each CPU in the system. In the very first implementation (82489DX), the LAPIC was a discrete circuit opposed to its thereafter implementation in Intel processors' silicon. There is typically one I/O APIC for each peripheral bus in the system. In original system designs, LAPICs and I/O APICs were connected by a dedicated APIC bus. Newer systems use the system bus for communication between all APIC components.