Michael: Attached are the 3 tree diagrams I found in the IBIS 5.0 Spec. for a tree diagram insertion pass. On the 3.1 diagram, I made a correction (a missing Vref) per the known issues document and also for a spelling typo. (Also, remove the spacing calibration pipes at the bottom.) On the Section 6b and 6c snippets, I kept the "|..." lines as originally shown, although some minor modification for consistency could be made. Bob -- Bob Ross Teraspeed Consulting Group, LCC http://www.teraspeed.com bob@xxxxxxxxxxxxxx Direct : 503-246-8048 Teraspeed Labs: 503-430-1065 Headquarters: 401-284-1827 Teraspeed is a registered service mark of Teraspeed Consulting Group LLC