Specifications

2 - 20
2.5 SCSI INTERFACE
The board's Small Computer System Interface (SCSI) controller option (U7 and associated
components) must be installed for this interface to be available. The SCSI interface uses a 50-pin
male header connector (J7) to interface with SCSI compatible peripherals. Table 2-17 shows the
pinout and signal definitions of this interface. Refer to your SCSI device documentation, or the
ANSI X3.131 SCSI specification (referenced in Chapter 4) for detailed information on the signal
functions. Be sure that the maximum total SCSI bus cable length, from the board's connector to
the most distant SCSI peripheral, does not exceed 18 feet.
Note
If the SCSI interface is not needed, you should either disable
it by using the SETUP utility or by placing a shorting block
on pins 1 and 2 of the SCSI connector (J7). When the
shorting block is in place, the system bypasses any attempt to
boot from the SCSI device, which can speed up the boot
process.
Table 2-17. SCSI Interface Connector (J7)
PIN SIGNAL FUNCTION
2 -DB0 Data Bit 0 (LSB)
4 -DB1 “ “ 1
6 -DB2 “ “ 2
8 -DB3 “ “ 3
10 -DB4 “ “ 4
12 -DB5 “ “ 5
14 -DB6 “ “ 6
16 -DB7 “ “ 7 (MSB)
18 -DBP Data Parity
26
TERMPWR
Termination +5VDC
32 -ATN Attention
34 GROUND Signal Ground
36 -BSY Busy
38 -ACK Transfer Acknowledge
40 -RST Reset
42 -MSG Message
44 -SEL Select
46 -C/D Control/Data
48 -REQ Transfer Request
50 -I/O Data Direction
25 --- Not used
1-49 (odd)
20,22,24 Ground Signal Grounds
28,30