Specifications

92 IBM Power 770 and 780 Technical Overview and Introduction
3. From J16 (T2) of the final expansion unit, connect to the second CEC enclosure,
SPCN 1 (T2).
4. To complete the cabling loop, connect SPCN 1 (T2) of the topmost (first) CEC enclosure
to the SPCN 0 (T1) of the next (second) CEC.
5. Ensure that a complete loop exists from the topmost CEC enclosure, through all attached
expansions and back to the next lower (second) CEC enclosure.
Figure 2-34 SPCN cabling examples
Table 2-33 shows the SPCN cables to satisfy various length requirements.
Table 2-33 SPCN cables
2.11 External disk subsystems
This section describes the following external disk subsystems that can be attached to the
Power 770 and Power 780:
򐂰 EXP 12S SAS Expansion Drawer (#5886) (supported, but no longer orderable)
򐂰 EXP24S SFF Gen2-bay Drawer for high-density storage (#5887)
򐂰 TotalStorage EXP24 Disk Drawer (#5786)
Note: Only the first two CEC enclosures of a multi-CEC system are included in
SPCN cabling with I/O expansion units. CEC enclosures number three and four are
not connected.
Feature code Description
#6006 SPCN cable drawer-to-drawer, 3 m
#6007 SPCN cable rack-to-rack, 15 m
SPCN Connections
I/O Units
I/O
Expansion
Unit
*J15(T1)
*J16(T2)
I/O
Expansion
Unit
*J15(T1)
*J16(T2)
I/O
Expansion
Unit
*J15(T1)
*J16(T2)
I/O
Expansion
Unit
*J15(T1)
*J16(T2)
Secondary 3 CEC
No connection to third
or fourth CEC
Secondary 2 CEC
No connection to third
or fourth CEC
P1-C1-T8 (SPCN0)
Secondary 1 CEC
P1-C1-T9 (SPCN1)
P1-C1-T8 (SPCN0)
Primary CEC
P1-C1-T9 (SPCN1)