Trailblazer 420/850S

   Jumper    Setting Description                      

     TE        OFF   Termination disabled             
               ON    Termination enabled              

     PK         -    Park / Spare jumper position     

    A2, A1,     -    These jumpers are used in        
     A0              combination to determine the     
                     drive's SCSI ID [See table 2]    

Table 1

Termination Enable (TE) Jumper

One of the requirements of the SCSI bus is that it be properly terminated. If more than one SCSI device is connected to the host, only the last device must be terminated. The Terminator Enable (TE) jumper, when installed, enables an active termination circuit, thereby terminating the SCSI bus. With the TE jumper removed, bus termination is disabled.

At the factory, Quantum configures the Trailblazer 420/850S hard disk drive with termination enabled; that is, with a jumper installed across the pins labeled TE. To disable termination, remove the jumper from the TE pins.

Note: There are no Termination Resistor Packs to remove on this drive.

Park (PK) Jumper

The Park (PK) jumper is used to place a spare jumper on the drive so that the customer has access to a jumper for later needs. This jumper position controlls no feature, a jumper in or not in this position does not effect the drive.

At the factory, Quantum configures the Trailblazer 420/850S hard disk drive with no jumper in place.

SCSI-Bus Device Identification (A0 - A2) Jumpers

Used in combination, the jumper settings across pins A2, A1 and A0 determine the Trailblazer 420/850S hard disk drive's SCSI-bus device I.D. By default, Quantum configures the drive with a SCSI ID of 6; that is, with jumpers installed across the pins labeled A2 and A1, and no jumpers installed across pins labeled A0.

To assign a different SCSI ID, change the jumper settings as shown in Table 2.

   A2        A1        A0      SCSI ID  

   OFF       OFF       OFF        0     
   OFF       OFF       ON         1     
   OFF       ON        OFF        2     
   OFF       ON        ON         3     
   ON        OFF       OFF        4     
   ON        OFF       ON         5     
   ON        ON        OFF        6     
   ON        ON        ON         7     

Table 2

Copyright 1995 Quantum Corporation
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