As a public service to the global signal integrity community, Amphenol FCI is making available their improved TRL (iTRL) de-embedding software. The iTRL method overcomes many of the limitations of standard TRL. With standard TRL, the accuracy of the de-embedded results depends on the equivalence between the calibration trace used for de-embedding and the actual traces on the test boards. Variations in impedance between the traces and launches of the calibration board and those of the test boards, can result in non-causalities in the de-embedded model. By making much more accurate models of the test board traces, the iTRL method overcomes the problems with TRL and yields cleanly de-embedded models of DUTs such as a connector with its PCB footprints.