ISO/IEC 11801 - Link and Channel Classes

Link and Channel Classes

The standard defines several classes of twisted-pair copper interconnects, which differ in the maximum frequency for which a certain channel performance is required:

• Class A: up to 100 kHz using elements category 1
• Class B: up to 1 MHz using elements category 2
• Class C: up to 16 MHz using elements category 3
• Class D: up to 100 MHz using elements category 5e
• Class E: up to 250 MHz using elements category 6
• Class E_A: up to 500 MHz using elements category 6_A (Amendment 1 and 2 to ISO/IEC 11801, 2nd Ed.)
• Class F: up to 600 MHz using elements category 7
• Class F_A: up to 1000 MHz using elements category 7_A (Amendment 1 and 2 to ISO/IEC 11801, 2nd Ed.)

The standard link impedance is 100 Ω. (The older 1995 version of the standard also permitted 120 Ω and 150 Ω in classes A−C, but this was removed from the 2002 edition.)

The standard defines several classes of optical fiber interconnect:

• OM1: Multimode fiber type 62.5 µm core; minimum modal bandwidth of 200 MHz*km at 850 nm
• OM2: Multimode fiber type 50 µm core; minimum modal bandwidth of 500 MHz*km at 850 nm
• OM3: Multimode fiber type 50 µm core; minimum modal bandwidth of 2000 MHz*km at 850 nm
• OM4: Multimode fiber type 50 µm core; minimum modal bandwidth of 4700 MHz*km at 850 nm
• OS1: Singlemode fiber type 1db/km attenuation