The latest revision of this standard calls out for tighter test limits when mating reference-grade connectors to standard-grade connectors.
There are several steps to be taken to reduce the uncertainty in loss testing of installed field links. The first step is to use the 1-cord method (e.g., reference) In the case of multi-mode, use an LED source and Encircled Flux compliant Test Reference Cords.
While we are on the subject of test reference cords, the standard recommends that use of reference grade connectors. Specifically in clause 7.3.4, the TIA-568 standard makes reference to the ANSI/TIA-526-7 and ANSI/TIA-526-14 which recommend the use of reference-grade connectors.
Reference-grade connectors are built to tighter tolerances which result in their having lower attenuation values in a mated connection. A pair of mated multi-mode reference-grade connectors, manufactured by Fluke Networks should offer an attenuation value equal to or less than 0.10 dB. Single-mode reference-grade connectors should offer an attenuation value less than or equal to 0.20 dB.
When mating a reference-grade connector to a standard-grade connector, you can expect better than the standard-grade loss value of 0.75 dB. The TIA-568 standard specifies that the loss limit for a mated pair of reference-grade to standard-grade connectors is ≤ 0.30 dB for multimode and ≤ 0.50 dB for single mode.
With the release of the V 5.1 firmware there are now limits that allow you to choose between the use of Reference Grade or Standard Grade connectors. While it is always the determination of the customer or the contract which test limit you should choose, if you are using the Test Reference Cords (TRC) supplied by Fluke Networks with the Certifiber Pro, you may select the “TIA-568.3-D Multimode (REF Grade)” limits which contemplate the use of reference grade connectors.
These (REF Grade) limits will use 0.30 dB as a loss limit for the first and last connector for multimode and 0.50 dB as a loss limit for the first and last connectors for singlemode.