IEC/TR 61156-1-2:2009(E) is a revision of the symmetrical pair/quad electrical transmission characteristics present in IEC 61156-1:2002 (Edition 2) and not carried into IEC 61156-1:2007 (Edition 3). This technical report includes the following topics from IEC 61156-1:2002
- the characteristic impedance test methods and function fitting procedures of 3.3.6;
- Annex A covering basic transmission line equations and test methods;
- Annex B covering the open/short-circuit method;
- Annex C covering unbalance attenuation.