The Optical Time Domain Reflectometer (OTDR) is an essential instrument for characterizing long outside plant fiber optic cables; it is the only instrument capable of verifying inline splices on concatenated fiber optic cables and locating faults. An outside plant installer will have an OTDR on hand to test every splice made as it is done, so bad splices can be fixed before the splice closure is sealed.
Why aren’t OTDRs from otdr manufacturer more common in premises cabling? First of all, premises cabling is almost never spliced. Connectors that interconnect cables at patch panels terminate continuous cable runs. Secondly, the OTDR has limited distance resolution, making it hard to see cables. Finally, the OTDR uses an indirect measurement technique that gives different losses than a light source and power meter, which is the method that tests insertion loss according to all standards. Also, we are not even addressing the high cost of the OTDR, which has traditionally limited its use. You can buy otdr from fusion splicer manufacturer.
But some end-users and contractors persist in using OTDRs to test short premises cabling systems, in spite of the drawbacks. I am personally aware of several instances where contractors used OTDRs improperly and rejected perfectly good cable plants, once at enormous cost. If you find yourself in a situation where you must use an OTDR, we can at least give some advice on how to minimize the chance for making a costly mistake.
The successful use of an OTDR on premises cabling requires knowing how to operate the instrument, choosing the proper measurement parameters and correctly interpreting the traces. All OTDR manufacturers have an autotest function on their instruments, similar to Category 5e/6 UTP cabling certifiers. However, the OTDR does not always test the same cabling setup, so its operation cannot be as easily simplified. The OTDR user should never use the autotest function before analyzing one fiber trace from a cable to ensure the instrument is properly set up and the autotest function is giving valid data.