AUI port on a router connects to what networking protocol?

Ethernet AUI

AUI cables have a D-type 15 pin connector. Pin assignments are as follows:Pin 1Control In circuit ShieldPin 2Control In circuit APin 3Data Out circuit APin 4Data In circuit ShieldPin 5Data In circuit APin 6Voltage CommonPin 9Control In circuit BPin 10Data Out circuit BPin 11Data Out circuit ShieldPin 12Data In circuit BPin 13Voltage PlusPin 14Voltage ShieldPins 7, 8 and 15 are not used.