Chapter 4: Link Fault Passthrough

4. Link Fault Passthrough

This converter supports link fault passthrough (LFP). Link status on one port is sent to the other port to identify the remote nodes.

If the twisted-pair port is unplugged, the converter stops transmission on the fiber port. This causes the remote fiber node link to fail. LEDs indicate the link failure on both twisted-pair and fiber ports.

If the fiber link fails, the converter restarts autonegotiation on the twisted-pair port but stays in the link failure state. This causes the remote twisted-pair node link to fail. LED also indicates the link failure on both twisted-pair and fiber ports.

Refer to Figure 4-1 for the normal status when the link succeeds. Refer to Figure 4-2 and Figure 4-3 for the error status when TP Cable A, Fiber Cable B, or Fiber Cable C fails to connect.

NOTE: LFP function only takes effect when S1-2 (see Figure 2-3) is enabled. Disabling S1-2 will turn LFP off.

indicates LNK/ACT LED Lit ° indicates LNK/ACT LED Off

Gigabit

Ethernet

switch

D

LFPLFP

B

A

Gigabit Ethernet switch

Remote station

TP

C

Fiber cable

TP

Figure 4-1. Normal status via a pair of LFPs.

Gigabit

Ethernet

switch

D

LFP

B

LFP

 

 

A

Gigabit Ethernet switch

Remote station

TP

C

Fiber cable

TP

Figure 4-2. The status when TP Cable A or D is broken.

Gigabit

Ethernet

switch

D

LFP

B

LFP

 

 

A

Gigabit Ethernet switch

Remote station

TP

C

Fiber cable

TP

Figure 4-3. The status when Fiber Cable B or C is broken.

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Black Box LPS500A-SM-10K-SC, LPS500A-MM-SC, PoE PSE Media Converter, LPS500A-MM-LC, LPS500A-SM-10K-LC Link Fault Passthrough