MAINT (EPN Maintenance Circuit Pack)
Issue 4 May 2002
10-1019555-233-123
In Figure 10-61, PROCR means a TN2404/TN790 for a RISC Processor circuit
pack, NETCON is the NEtwork Control circuit pack (TN777B) (the Active
NETCON circuit pack in a high or critical reliability system), and MB stands for the
EPN Maintenance circuit pack. Figure 10-61 shows the connectivity for a system
with duplicated Expansion Interface Links.
Figure 10-61. EPN Maintenance Circuit Pack Message Flow
The EPN Maintenance circuit pack must be physically inserted into the dedicated
slot marked Maintenance in the A carrier of the EPN. The serial links from the
EPN Maintenance circuit pack to the Expansion Links physically connect from this
dedicated slot to slots 2A01 and 2B02 (2B02 is used only if there are redundant
Expansion Links). The serial link from slot 2A01 to the maintenance slot is
hard-wired into the backplane of carrier A, whereas the serial link from slot 2B02
to the maintenance slot is a ribbon cable connecting the two slots. The serial link
from the EPN Maintenance circuit pack to the terminal is also a ribbon cable which
plugs into a connector labeled TERM on the back of carrier A.
The maintenance strategy for the EPN Maintenance circuit pack consists of
checking the integrity of the communications path to/from the EPN Maintenance
circuit pack, testing individual hardware components on the EPN Maintenance
circuit pack, and keeping the system level LEDs up-to-date. The individual
hardware components include the serial interfaces which handle the serial links
connected to the EPN Maintenance circuit pack. There are three serial interfaces,
one for each possible Expansion Interface circuit pack and one for the Manager I
(G1) or G3MT terminal.
P
R
O
C
R
N
E
T
C
O
N
TDM
BUS
FIBER
SERIAL LINK
PPN EPN
FIBER
SERIAL LINK
M
G
R
1
E
X
P
I
N
T
F
E
X
P
I
N
T
F
E
X
P
I
N
T
F
E
X
P
I
N
T
F
M
A
I
N
T