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Figure 25:An example of a multi Server system
A system with only one ELU31 board still requires a RING cable TSR
901 1226/3000 for ELU31) running from the TX port to the RX port on
the same board
The base stations are connected via a MDF or MDM with 2 communica-
tion pairs and if needed one express power pair. Connections for one
express power pair (EPP) is provided both on the ELU31 board and on
the base stations. It is possible to use 2 EPP pairs to lower the cable
resistance and increase the line length to the base station even more,
see chapter “Appendix A:RFP Power Consumption” in “Installation
Guide Base Station”. This however requires some special arrangements
when connecting the two EPP pairs in parallel, see figure 24 Connec-
tions when using 2 EPP pairs on page 47. Care should also be exercised
not to short circuit the wires or swap polarity.
At the initial time when the system is installed and the ring is connected
for the very first time it is a requirement that the ring cabling is complete.
This is the first time the ring boards assume their roles and if the ring is
not complete the roles cannot be decided. Until the synchronization ring
is complete no base stations will start.
When the system is up and running and a Media Gateway is powered
down and up or a ELU31 board is replaced or added, only base stations
connected to these units will be affected.
Note:
Too big or too fast alterations in the system may lead to that the
synchronization ring gets disrupted. When this happens, the
whole system will restart.
SRV 1
SRV 2
SRV 5
SRV 3
SRV 4
sync
MDM
MDF
MDM
MDM
MDF
MDF
MDF
MDM
SYNC
SYNC
SYNC
SYNC
Base
station
Base
station
Base
station
Base
station
Base
station
Base
station
Base
station
Base
station
