Asus P2B-DS - Manual (Page 33)

ASUS P2B-D/P2B-DS User’s Manual 33
III. INSTALLATION
Connectors
III. INST
ALLA
TION
21. Fast (50 pins)/Wide (68 pins)/Ultra2 (68 pins) SCSI Connectors
This motherboard has onboard 50-Pin Fast SCSI connector for 8-bit SCSI de-
vices, 68-Pin Wide SCSI connector for 16-bit SCSI devices, and 68-Pin Ultra2
SCSI connector for 16-bit differential SCSI devices.
P2B-D/P2B-DS Onboard SCSI Connectors
50-pin Fast
SCSI II Connector
68-pin Ultra2
SCSI Connector
68-pin Wide
SCSI Connector
1
1
R
NOTE: Up to 15 devices can be connected with 50-Pin Fast-SCSI and 68-Pin Ultra-
Wide SCSI combined.
The onboard Adaptec AIC-7890AB chipset (optional) incorporates an advanced multimode
I/O cell that supports both single-ended (SE) and Ultra2 devices. With Ultra2 devices, the
SCSI bus platform performs at full Ultra2 speeds (up to 40 MB/sec in 8-bit mode and up to 80
MB/sec in 16-bit mode) and extended cabling 12m (or 25m in a point-to-point configuration).
When an SE device is attached, the bus defaults to an SE speed and cable length.
In mixed environments of Ultra2 and SE devices, the onboard host adapter can be coupled with the
Adaptec AIC-3860 transceiver chipset (optional) to bridge the compatibility gap. By dividing the
SCSI bus into independent SE and low voltage differential (LVD) segments, the transceiver chipset
supports legacy devices without limiting performance and cable length on the LVD segment.
P2B-D/DS Mixed Ultra2 and Single-Ended Device Configuration
1
R
1
Adaptec AIC-3860 Chipset
Adaptec AIC-7890AB Chipset
PCI Bus
L
LVD Mode
S
Wide SCSI Connector
Ultra2 SCSI
Connector
PCI-to-Ultra2 (LVD)
SE Mode
Ultra2 Devices
Single-Ended Devices
Scanner Tape
Disk 2 Disk 3 Disk 1
CD-ROM
Ultra2 SCSI uses the same connectors and cables as UltraSCSI, so upgrading is easy and cost-effective.