3G Cdma2000 is based on the original IS-95 and IS-95A CDMA standards, as well as the 2.5G IS-95B air interface. While upgrading, Cdma2000 maintains backward compatibility with existing IS-95, IS-95A and IS-95B equipments. Thus, Cdma2000 allow wireless carriers to introduce a family of new high data rate Internet access capabilities within existing systems.