ISO/IEC TS 11801-9903:2025

ISO/IEC TS 11801-9903:2025 establishes modelling of limits for mixed-mode transmission parameters within and between two pairs of balanced cabling. This document consists of a detailed description of matrix modelling and gives explanations on how to convert matrices, by using the S to T and T to S matrix conversion. Further it consists of terms and definitions used, how specific parameters are modelled, alternative calculation and signal-to-noise ratio (SNR) modelling.
Chain parameters and alternative approaches and formulas are described for combining component cable and connector transmission parameters into cabling link and channel transmission parameters. S-parameter limit matrix formulas are covered, which can be transformed into T-parameter limit matrices for use in chain parameter link and channel limit formulas. The formulas are applicable to all transmission parameters for forming complete differential-mode, mixed-mode, and common-mode link and channel models.
Terms and definitions used for modelling are discussed, together with how modelling is done for specific transmission parameters. Alternative calculation models are explained, and the SNR modelling introduced.
This second edition cancels and replaces the first edition published in 2021. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) the expansion of the list of specified parameters to include mixed-mode mode-conversion and related unbalance attenuation parameters;
b) the addition of an informative annex covering the topic of signal-to-noise ratio and its relation to the S-parameter matrix channel model.