The technologies used to communicate between chips and printed circuit boards (PCB) have been undergoing quite a few changes in recent years. The peripheral component interconnect (PCI) bus still has plenty of life left in it yet but for those developers requiring higher speed interconnects, of the order of 2 Gb/s and beyond, a number of new interconnect standards have emerged. There are no clear winners and losers yet, and the situation is particularly unclear at the backplane, which is expected to play host to a battle between two rival technology camps. In the race to succeed PCI, the main contenders to have emerged are PCI Express, RapidIO and HyperTransport.