Specifications

InstallationEP-BXBS
Page 3-13
Section 3-6
Adaptec SCSI Setup
Introduction
The EP-BXBS mainboard features the advanced Adaptec AIC-7890 Ultra-2 Wide
SCSI controller. This controller provides support for Low Voltage Differential
(LVD) SCSI devices as defined under the Ultra-2 section of the SCSI-3 standard.
LVD SCSI devices allow for data transfer rates of up to 80 Mbytes/sec and can
use cable lengths of up to 12 meters! Additionally the AIC-3860 Adaptec control-
ler is also provided for backwards compatibility with single-ended (SE) legacy
SCSI devices such as SCSI-1, Fast, Fast Wide, Ultra and Ultra Wide.
Hardware Setup and Connector Descriptions
The motherboard can have attached a total of 15 SCSI devices. The 15 de-
vices can be a combination of LVD Ultra-2 devices and/or SE Legacy devices
but note that the SE Legacy controller can support up to 8 devices only!
Provided on the motherboard are three SCSI connectors. The first two being SCJ1
and SCJ2 are provided for single-ended (SE) legacy SCSI devices and will oper-
ate at a data transfer rate of 40 Mbytes/sec (max.) using the 68-pin “Wide” connec-
tor and 20 Mbytes/sec (max.) using the 50-pin “Narrow” connector. It is strongly
recommended that all legacy SCSI devices be connected to either one of these two
connectors. Due to the design characteristics of SE mode devices the cable length
per connector should never exceed 3 meters with up to 4 SCSI devices and 1.5
meters with up to 8 SCSI devices.
External SCSI devices can be connected to the SCSI bus through the
use of the included “external SCSI-2 port adapter.” To use external
SCSI devices simply use onboard connector SCJ2 with an internal 50-
pin SCSI cable. One end of the cable must attach to SCJ2 and the other
end connects to the external port adapter. Internal SCSI devices can still
be used, but just not on the ends of the cable.