Hi All, The latest version of the Backchannel BIRD (draft 7) has been uploaded on the ATM website and is available here: http://www.vhdl.org/ibis/macromodel_wip/archive/20140314/ambrishvarma/Backchannel%20support%20BIRD%20147%20draft%207/Backchannel_BIRD147_Draft7.docx Or http://tinyurl.com/bcibird7 The major changes in this version include the following. I have removed the possibility of defining Bits in anything but binary values as that is the fundamental notation for bits. This will remove a lot of present and future confusion about how Bits are to be defined. I have also described how to generate PRBS using a particular implementation of the LFSR. Other editorial changes and fixes are also included in this version. Thanks to Vladimir, Arpad and Bob for sending me feedback and working with me on improving this. Please let me know if there are any questions. Thanks, Ambrish. Ambrish Varma. Cadence Design Systems.