Analysis of Effect of Some Parameters of Symmetrical-Copper-Twisted-Pair on Quality of ADSL Service

This paper is analyzing how some symmetrical-cooper-twisted-pair parameters take effect to quality of ADSL services. The treated parameters are insulation resistance, loop resistance and attenuation (on several significant frequencies). As the parameter of quality of service the bit-rate (both up-stream and down-stream bit-rate) is used. The testing transmission line is twisted pair placed in low-band telecommunication cable, with variable length (up to 8000 meters), and with 0.4 mm conductor diameter. We treated two types of low-band telecommunications cables - cable with paper-based insulation and lead-shield (approximately 25 years old), and cable with polyethylene-based insulation and aluminium-shield (2.5 years old). Basic theory of electrical loops is given at begin, measurements results and conclusion follow after that.