For multimode fiber, the loss is about 3 dB per km for 850 nm sources, 1 dB per km for 1300 nm. 5 dB/km max per EIA/TIA 568) This roughly translates into a loss of 0. This type of testing is the most accurate testing available and is the most accurate characterization of the fiber optic system's apability. Testing with. this document is the property of JDSU. No part of this book may be reproduced or utilized in any form or means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without pe n optical fiber to a distant receiver. It includes a collection of references to the main measurement methods and gives an indication of which are most suitable for installed cable links, depending on the required. Fiber cable quality is evaluated across multiple dimensions: Each parameter requires a specific test method and acceptance threshold. Visual inspection identifies contamination, scratches, cracks, and endface defects that directly affect optical performance. Visual inspection is always performed. After fiber optic cables are installed, spliced and terminated, they must be tested.