Asus PCI-SC896 User Manual - Page 12

1. Introduction 1. Introduction 1.3.4 Wide Ultra2 SCSI The PCI-SC896 has full support for Wide Ultra2 SCSI. This interface is an extension of the SCSI-3 family of standards that expands the bandwidth of the SCSI bus to allow faster synchronous data transfers, up to 80 Mbytes/s. Wide Ultra2 SCSI provides a doubling of the data rate over the Ultra2 SCSI interface, while it increases cable lengths and allows a larger number of devices on the cable than Ultra2 SCSI interfaces. Special SCSI cables are specified for operation with Wide Ultra and Ultra2 SCSI devices, and you must consider the total number of devices and the length of your SCSI bus when setting up your system. See Chapter 2, Installing the PCI-SC896 Host Adapter for a detailed explanation of SCSI bus connections. When you purchased the PCI-SC896 host adapter kit, the cable provided in the kit is matched for a Fast/Ultra/Ultra2 SE or LVD operation. This cable also has built-in LVD termination since most Ultra2 hard disk drives are not made with onboard LVD termination. Standard Cables Maximum Bus Length (1) STA Term Single-Ended LVD Maximum Devices Wide Ultra SCSI 1.5M Wide Ultra SCSI 3.0M (3) 8 (3) 4 Wide Ultra2 SCSI (2) 12 16 (1) This parameter may be exceeded in point to point and engineered applications. (2) Single-ended and high-power differential are not defined at Ultra2 speeds. (3) LVD was not defined in the original SCSI standards for this speed. If all devices on the bus support LVD, then 12-meter operation is possible at this speed. However, if any device on the bus is single-ended only, then the entire bus switches to single-ended mode, and the distances in the single-ended column apply. 12 ASUS PCI-SC896 User's Manual