12
6 x 4 ELECTRONIC SCSI SWITCH
2.3.2 G
ENERAL
H
ARDWARE
D
ESCRIPTION
The 6 x 4 Electronic SCSI Switch’s rear panel identifies each of the independent
SCSI ports. SCSI ports A, B, C, and D have two daisychained connectors per port,
and SCSI ports 1, 2, 3, 4, 5, and 6 have single connectors for installation of SCSI
devices. You can install the SCSI Switch at any point on the SCSI bus.
Each port has internal termination that can be turned on or off from the LCD
panel. External “termination power” (TERMPWR) for devices and terminators are
provided by internal resettable fuses.
The SCSI Switch does not require a device ID and is completely transparent to
all computers and peripherals on the SCSI bus. No additional software is needed
for installation and operation. A universal switching power supply automatically
adapts to input voltages between 105 VAC and 240 VAC.
2.3.3 U
LTRA
2 SCSI C
OMPATIBILITY
The SCSI Switch supports Ultra2 SCSI, 80-MBps (wide) SCSI host adapters,
computers, and peripherals in asynchronous and synchronous mode. (SW487A-R2
also supports Ultra160 SCSI, 160-MBps devices.) The SCSI Switch conforms to
ANSI X3.131 and X3T9.2 specifications for single-ended devices. Disconnect and
reselect functions are fully supported to ensure complete SCSI compatibility.
2.3.4 SCSI S
WITCH
I
NSTALLATION
Ports A, B, C, and D are fully bidirectional to ports 1, 2, 3, 4, 5, and 6 (see
Figure 2-1). You determine where to connect computers, host adapters, and
peripherals. In general, if daisychained ports are required for connection to
external peripherals, use ports A, B, C, and D. See Figure 2-2 for a typical
installation.
NOTES
1. For proper operation of any SCSI bus, there must not be a “hanging”
line or cable. Termination should be enabled on active SCSI ports that
are not connected through to another port.
2. Connections can be made to either connector on the appropriate port.
3. In Figures 2-1 and 2-2, “Term” indicates where terminators should be
installed.
The LCD panel is used to select port connections and enable or disable each
internal SCSI-port terminator. Refer to
Chapter 4
for complete instructions on
operating the LCD keypad.
