HP D2200sb Serial Attached SCSI technology, 3rd edition - Page 5

Differential signaling reduces the effects of capacitance, inductance, and noise experienced by parallel SCSI at higher speeds. In differential signaling, the positive signal minus the negative signal equals 1500-900 = 600mV or 900-1500 = - 600mV (Figure 2). SAS communication operates in full duplex mode, which means that each PHY can send and receive information simultaneously over the two wire pairs. Figure 2. Examples of differential signaling Table 2 lists the physical link rates for SAS and SATA. Table 2. Physical link rates per direction Physical link rate 1.5 Gb/s 3 Gb/s 6 Gb/s Generation Bandwidth for a 1x connection SAS-1, SAS-1.1, SATA Revision 150 MB/s 1.0 SAS-1, SAS-1.1, SATA Revision 300 MB/s 2.0 SAS-2, SAS-2.1, SATA Revision 600 MB/s 3.0 4x bandwidth 600 MB/s 1200 MB/s 2400 MB/s 5