A cable tester (CAT) is a measuring device with which cable properties such as impedance, resistance or attenuation can be measured. Modern cable testers address the increasing demands of high-speed networks on the quality of the passive network and can measure crosstalk parameters such as Near End Crosstalk( NEXT), Far End Crosstalk ( FEXT) and Equal Level Far End Crosstalk( ELFEXT) as well as attenuation and return loss.
Cable testers, which are used in the field and are therefore called field testers or field meters, are qualified and standardized in classes just like data cables. IEC document 61935-1 , available since March 2003, describes and classifies the electrical characteristics of field testers. These include, among others, the noise floor of the field tester or the crosstalk. The classification recognizes class 2E, suitable for measurements on category 5E (cat 5E) cables according to EN 50173, and class 3 for category 6, link class E cables.
Test equipment for testing network cabling is also called qualifiers. Such qualifiers can be used to determine whether the cabling meets the data rates ofEthernet, starting with Fast Ethernet with transmission rates of 100 Mbit/s through Gigabit Ethernet up to 10 Gigabit Ethernet. All transmission media are included. Another special group of devices are the TDR measuring devices, which work time-oriented and can analyze errors over the cable length.