Fibre Cable Power Loss Calculations

When having fiber optic cables tested for power loss, make sure the pass/fail limit is determined from a cable loss calculation rather than a simple 5 db limit.

Calculating loss limits based on a building-cabling standard

Using TIA/EIA568 as an example, calculate the loss limit at 850nm for a 62.5mm fiber cable that is 127m long. The cable has a connector on each end of the permanent link with one splice. In the TIA/EIA568 standard, the following maximum loss values are given:

In order to meet the requirements of the TIA/EIA568 installation standard, the test limit for a 127m cable should be 2.28 dB or less. Any power loss measurement beyond 2.28 dB for this link indicates an installation does not in conform to the TIA/EIA568 standard.

Conclusion

Do not accept a Power Loss Reading without a calculated Power Loss Limit. It is no longer acceptable to consider a result that is less than 5 dB as ok" even if the network still runs, especially as network speeds increase to 100 Mbps and beyond. Always demand a calculated Power Loss Limit for each power loss measurement in your fiber optic network so you can ensure the installation is performed to required industry standards.

Send mail to with any comments about this web site.
Last modified: 04 April 2010

Fibre Cable Power Loss Calculations

HOME

SERVICES

WHO WE ARE

PORT NUMBERS

PREPRESS

WINDOWS 7 and VISTA

WINDOWS XP

WINDOWS 2000

WIMDOWS 2003

WINDOWS NT4

LINUX

INFECTIONS

GLOSSARY

LINKS

GOOGLE

Calculating loss limits based on a building-cabling standard

Conclusion