Product manual

38 Product Manual - Hawk 2 Family (Wide bus) SCSI-2 (Volume 1), Rev. A
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J2
Jumper
Installation Jumper Function Description
TE (ST12400W only)
On With the jumper installed, the On-board (non-removable) terminator circuits are enabled
(connected to the I/O lines). Default is jumper installed.
Off Terminator circuits not connected to I/O lines.
TP TP
Off Off No terminator power is connected to drive terminators or SCSI bus I/O pin 26.
On Off Drive supplies its own terminator power only. Jumper on this position is factory default.
Off On Drive supplies power to I/O pin 26 of SCSI bus; none to internal terminators. When drives
have differential I/O circuits, a jumper on the right TP position may be needed to power
external terminators (see system documentation). The ST12400WD drive has differential
I/O circuits which have no terminator circuits on the drive. The ST12400WC drive has no
provisions for terminators and no provisions for terminator power in the 80 pin I/O connector.
The TP jumpers do not apply to model ST12400WC.
On On Drive supplies terminator power to itself (internal connection) and to I/O pin 26 of SCSI bus.
This is a legal jumper setting.
TP Position A
On This horizontally positioned jumper across the two TP positions nearest PCB edge, con-
nects terminator power from SCSI bus I/O pin 26 to the drive's internal terminators (for
Model ST12400W only).
Off See above explanations for TP jumpers.
J1-Auxiliary, J6
Jumper
Installation Jumper Function Description
A
3
,A
2
,A
1
,A
0
Drive ID on SCSI Bus (J1-auxiliary or J6 may be used as the ID circuits are wired in parallel).
The drive ID is binary coded positionwise i.e., jumper in position A
3
is drive ID 8, A
2
is drive
ID 4, position A
1
is ID 2, position A
0
is ID 1 and no jumpers is ID 0. Default is ID = 0. Both J1-
auxiliary and J6 should not be used at the same time, because at some future time when the
ID is changed the user could fail to configure both J1-auxiliary and J6 the same. Model
ST12400WC does not have J1-auxiliary.