The PCI Dual Channel Ultra3 SCSI Adapter is a 64-bit adapter and is an excellent solution for high-performance SCSI applications. The adapter provides two SCSI channels (busses). The two internal ports can be used for internal SCSI solutions on supporting pSeries and RS/6000 systems. The two external ports provide connectivity to supported IBM external subsystems. In order to achieve an Ultra3 SCSI bus data rate of up to 160 MBytes per second and also maintain a reasonable drive distance, the adapter utilizes Low Voltage Differential (LVD) drivers and receivers. To fully utilize this Ultra3 160 MBytes per second performance, all attaching devices or subsystems should also be Ultra3 LVD devices. But, if Ultra2 and Ultra3 devices coexist on the same bus, each device will operate at its rated speed. For lower speed single-ended (SE) devices, the SCSI bus will switch to single-ended (SE) performance and interface at the lower SE bus data rate of the device.