3Com 5104M-FL1 Example Fiber Link Through Patch Panels, Meter Fiber Link Through Two Patch Panels

Example: Fiber Link Through Patch Panels

Figure 2-2 illustrates two ONline Concentrators are separated by 1700 meters of fiber cable with two patch panels in between. If we use 50/125 fiber cable, the optical power budget according to Table 2-3 is 10.0 dB.

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		Patch 1700 meters Patch
		Panel		Panel
	Connectors			Connectors
1.7 Km Fiber Cable		8.5 dB loss worst case using 5 dB/Km loss fiber cable
Two ST Patch Panel		1.5 dB loss worst case
Path Loss		10.0	dB

Figure 2-2. 1700 Meter Fiber Link Through Two Patch Panels

Total path loss in this example is 10 dB. Because the overall optical power budget for 50/125 cable is 10.0 dB, this leaves 0 dB to spare.

In addition, the received optical power is on the outer edge of the specification. As defined in Table 2-3, the peak received power range for 50/125 cable is -29.5 dB. Adding the path loss of 10.0 dB to -19.5 dB equals -29.5.

This may cause the 10BASE-FL Module Port Status LED to signal a no light condition. If a no light condition occurs, you must reduce the optical path loss by shortening the cable or by eliminating some of the optical connectors.

2 - 12 ONline Ethernet 10BASE-FL Installation and Operation Guide