Some Administrations use new manual or automatic methods of equalizing attenuatton distortion,
e.g. equalizers based on the Cosine function, using frequencies which do not appear in the list of additional measuring frequencies recommended by the CCITI'.
ITU-T G.332-1989 history
1989ITU-T G.332-1989 12 MHz Systems on Standardized 2.6/9.5 mm Coaxial Cable Pairs - International Analogue Carrier Systems (Study Group XV) 11 pp