Loop Telecom AM3440 series, User Manual, Page: 16 / 70

CHAPTER 4 MAINTENANCE
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4. MAINTENANCE
4.1. Near End Loopback
The near end loopbacks such as backplane loopback, payload loopback, local loopback, and line
loopback, are activated by the TDMoE. The loopbacks are at the near end facility. The following
paragraph describes each loopback in detail.
4.1.1. Backplane Loopback/Time Slot Interface Loopback (FPGA to Backplane Loopback)
Backplane loopback is illustrated in Figure 4-1. The incoming signal is immediately looped back to
Backplane after entering FPGA without going through FPGA process. The outgoing signal then passes
TDMoE Chipset and Ethernet Switch and arrives in the remote physical link.
4.1.2.
Payload Loopback (FPGA to Ethernet Loopback)
Payload loopback is illustrated in Figure 4-1. The signal is looped back to TDMoE Chipset from FPGA
after it goes through Ethernet Switch and TDMoE Chipset. The signal then passes Ethernet Switch and
arrives at the remote physical link.
4.1.3. Local Loopback (FPGA to Backplane Loopback)
Local loopback is illustrated in Figure 4-1. The incoming signal is looped back to Backplane from FPGA.
The outgoing signal then passes TDMoE Chipset and Ethernet Switch and arrives at the remote
physical link.
4.1.4.
Line Loopback (TDMoE Chipset to Ethernet Loopback)
Line loopback is illustrated in Figure 4-1. The signal is immediately looped back to Ethernet Switch after
entering FPGA without going through FPGA process. The signal then arrives at the remote physical
link.
Figure 4-1 Loopback Diagram