With the liberalization in telecommunications, unbundling becomes common-place in telecommunications networks. The unbundling of the access network increases the number of operators that may provide services within a common access network cable. In this context, unbalance is not only related to the transmission performance of the services, but also strongly related to EMC performance of the services. The LCL of telecommunication lines or telecommunication ports is a measure of the degree of unwanted transverse signal produced at the terminals of the network due to the presence of a longitudinal signal on the connecting leads. Considering the frequency range of broadband services such as ISDN, ADSL, ADSL2, ADSL2plus, VDSL and VDSL2, this Recommendation presents the method for measuring Longitudinal Conversion Loss for the frequency range from 9kHz to 30MHz and presents the suggestion of the admissible value for the unbundling condition.