0 100base-tx adapter mode operation, 1 100base-tx transmit clock generation, 2 100base-tx transmit blocks – Intel 82555 User Manual

Page 17: 1 100base-tx 4b/5b encoder, Table 2. 4b/5b encoder, 100base-tx adapter mode operation, 100base-tx transmit clock generation, 100base-tx transmit blocks, 100base-tx 4b/5b encoder