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Networking Fundamentals · Intermediate

Insertion Loss

The total signal loss caused by inserting a component or cable segment into a link, measured in dB.

Definition

In fiber, each mated connector pair commonly adds up to about 0.75 dB under TIA limits (typical 0.3 dB) and each fusion splice about 0.1-0.3 dB. Certification tests compare measured insertion loss with the calculated loss budget.

Example

A fiber link with two connector pairs and 500 m of multimode measures 1.8 dB insertion loss.

Exam tip

Every connector and splice adds loss; dirty connectors add much more.

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