Hi All, The latest version of the Backchannel BIRD (draft 6) has been uploaded on the ATM website and is available here: http://www.vhdl.org/ibis/macromodel_wip/archive/20140211/ambrishvarma/Backchannel%20support%20BIRD%20147%20draft%206/Backchannel_BIRD147_Draft6.docx Or http://tinyurl.com/bcibird6 This is a cleaned up version with all the changes accepted. Only changes from the last version (draft 5) are marked up. Those changes include an example of the backchannel communication and clear instructions on what the Tx/Rx AMI model do when receiving instruction from the other end of the link. Please let me know if there are any questions. Thanks, Ambrish. Ambrish Varma. Cadence Design Systems.