Archive PYTHON 4322 Product Description Manual page 40

INSTALLA TlON
SCSI-1/SCSI-2 Interface
The Python 4322 and 4542 drives allow you to choose either SCSI-lor SCSI-2 as the default interface with
the computer system. However, the factory default for the drives is the SCSI-2. (Chapter 5 provides
summary information about the SCSI-1 and SCSI-2 interfaces.)
The SCSI-1 interface conforms to the ANSI X3.131-1986 standard. SCSI-2, which conforms to ANSI
X3T9.2, Revision 10, is a standard that augments the SCSI-1 command set and generally includes everything
in SCSI-I.
If the hardware default setting is SCSI-2 for power up, issuing a CHANGE DEFINITION command allows
SCSI-1 to be selected until the next power up. To tum data compression OFF, the host computer issues a
SCSI MODE SELECT command.
Terminator Power
At the rear of the Python 4322 and 4542 drives, a 2-pin header allows you to enable +5-volt terminator
power if needed for terminators or other SCSI devices. The factory default for internal Python DDS-DC
drives is with terminator power disabled Gumper shunt over one pin). To enable terminator power, place the
jumper shunt over the two pins. (See Figure 3-1 for the 4322 drive and Figure 3-2 for the 4542 drive.) Be
sure it is firmly in place.
CAUTION:
If the jumper is installed, be careful not to short the TERMPWR signal to ground.
The terminator power fuse is located beside the terminator power jumper to prevent damage to drive
components in case the terminator power is shorted. If terminator power is enabled and the SCSI cable is
connected upside down, this fuse may blow to prevent damage to the drive itself. In that case, return the
drive to an authorized repair facility.
Serial Port
A unique feature of the Python internal 4322 and 4542 drives is the 3-pin serial port available at the rear of
the drive unit This serial port allows access to internal drive diagnostics stored in firmware. These internal
diagnostics allow standalone testing of the drive through connection to an external computer.
Should this capability be needed, contact your Archive sales representative about receiving the Archive
Python Serial Port Diagnostics Kit, which includes a TTL logic converter, manual, cables, and host PC
software.
In addition to the serial port connector, another larger connector on the PCB at the rear of the drives allow
access to the drive for manufacturing testing. (See Figures 3-8 and 3-9.)
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