I read on Kraus' "Electromagnetics", 4th edition (p 583), that four-wire transmission lines (in a quadrupole configuration - the conductor with the same polarity are in diagonal) improve shielding. + - - + I tried to find some more information about this sort of transmission lines but I couldn't find anything sensible. Are these T.L. used for data communications, how can one compute the characteristic impedance (considering the the lossy case too), are there tables with properties based on geometrical specs? Are there experimental studies? (And so on...) I would like to know if it's possible to adapt a standard Ethernet cable to mimick this sort of transmission line to improve its shielding from external interference. Any pointers?