Zte ZXDSL 9210 (V3.1), Техническое руководство

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ZXDSL 9210 (V3.1) Broadband Universal Access Equipment Technical Manual
4-16
The operating principles of PSUN are shown in Fig. 4.2-6.
PSUN board
Subscriber
line
PSTN
Transformer Transformer
Peripheral
components
Over-current and
over-voltage
protection
components
Fig. 4.2-6 Operating Principles of PSUN
Two relays are used in each subscriber line. The relay outside the splitter provides the
test function while that inside the splitter provides the protection. Test lines
corresponding to odd channels of subscriber lines are converged and those
corresponding to even channels of subscriber lines are converged; all test and
protective buses are converged to the LTC, which implements protective switchover
and tests.
The operating principles of PSUT are shown in Fig. 4.2-7.
2 pairs of test
buses
PSTN
ATIGN
Over-current and
over-voltage
protection
components
Subscriber
line
PSUN board
Splitter
Relay
Relay
2 pairs of
protection buses
Fig. 4.2-7 Operating Principles of PSUT
4.2.6 EICM
4.2.6.1 Functions of EICM
EICM takes the Ethernet uplink base plate as its base plate. EICM is equipped with a
Layer 2 Ethernet uplink subboard (FEC) or an enhanced Ethernet subboard (FNC), or
two subboards. Different subboards provide different Ethernet user interfaces or uplink
ports. EICM is categorized as EICMA, EICMB, and EICMC.