MR0012J 9710 System Assurance Guide 3-9
Data Interfaces
Data Interfaces
Refer to the 9840 Tape Drive System Assurance Guide, MT 5003, for 9840 data
interface information.
The LSM has three data interfaces available:
Small Computer System Interface (SCSI) for all drives
Federal Information Processing Standard (FIPS) interface for 4890s
Fibre Channel for 9840s

4890 Data Buses

You may order FIPS bus drives, SCSI bus drives, or both. FIPS and SCSI are not
available on the same drive.
Two FIPS data bus terminal blocks are present on a drive. Each bus in this
definition includes the Data In, Data Out, Tag In, and Tag Out lines. You can
use the two terminals for two data buses, use only one terminal block and
terminate the other, or use the second terminal block for daisy chaining.
Note: The AS/400 I/O port does not allow daisy chaining of the 4890 Drives.
Each SCSI drive has two SCSI data bus connectors. You may use only one SCSI
data bus input per drive. The other connector must be terminated, or it can be
used for daisy chaining in a non-AS/400 environment, but it cannot be used for
a second data bus.

DLT Data Buses

Each DLT has two SCSI data bus connectors. You can use only one SCSI data
bus input per drive. The other connector must be terminated , or it can be used
for daisy chaining, but it cannot be used for a second data bus.
I/O Cabling Limits
Examine Figure 3-7 on page 3-11 and Figure 3-8 on page 3-12 while you read
the following discussion.
Only one SCSI control line can exist. The other SCSI port, on both the SCSI card
and the I/O tower, is reserved for daisy chaining; it should be terminated on the
SCSI control interface card.
Two RS423/RS232 control lines can exist on the I/O tower. Each control may be
connected to a separate AS/400.
Six FIPS data buses can exist on the I/O tower. Each bus in this definition
includes the Data In, Data Out, Tag In, and Tag Out lines. If you are using two-
bus FIPS drives, each connected at the I/O tower to two FIPS buse s, then no