For structured cabling systems, the standard requires the use of category 5e, 6 and 6A (100 MHz, 250 MHz et 500 MHz respectively) twisted, symmetrical 4-pair cables with an impedance of 100 Ω ).
The cable can be of the following type:
* unshielded u/uTP (unshielded Twisted Pairs)
*Shielded F/uTP (Foiled Twisted Pairs)
* Double shielding SF/uTP or S/FTP.
Normally Network data cables are made up of four pairs arranged
inside a sheath according to a specific layout, which is necessary to
reduce attenuation and crosstalk problems. This layout consists of
twisting the pairs of conductors individually.
These pairs are identified using standard colours. Each of the
pairs has a different pitch, and is in turn twisted differently
inside the outer sheath. The conductor size permitted by the standards is between 22 and 26 AWG: 24 AWG is the most commonly used in all cases.