With reference to T568B above;
      ATM 155Mbps uses pairs 2 and 4 (pins 1-2, 7-8)
      Ethernet 10Base-T uses pairs 2 and 3 (pins 1-2, 3-6)
      Ethernet 100Base-T4 uses pairs 2 and 3 (4T+) (pins 1-2, 3-6)
      Ethernet 100Base-T8 uses pairs 1,2,3 and 4 (pins 4-5, 1-2, 3-6, 7-8)
      Token-Ring uses pairs 1 and 3 (pins 4-5, 3-6)
      TP-PMD uses pairs 2 and 4 (pins 1-2, 7-8)
      100VG-AnyLAN uses pairs 1,2,3 and 4 (pins 4-5, 1-2, 3-6, 7-8)