I'm interested to know how y'all interpret IPC-2221, section 12.4.1 "Specimen A and B (Plated Hole Evaluation)..." "Spacing between holes shall be representative of the printed board. Conductors shall be included in between the holes on each signal layer." I have the interpretation that the spacing between the holes (with the traces between them) will be determined by the worst case pad to trace spacing on the design. So, if there are 6 mil lines and 6 mil spaces on the internal layers but only 8 mil lines and 8 mil spaces on the outer layers, I would have to set up the coupon with the 6 mil line and space throughout the entire coupon stack. This seems to make the outer layer of the coupon then NOT match the outer layer of the board and the coupon may fail where the board may not. Do you make an extra set of A & B coupons for each different spacing configuration? Do you mix the hole to hole and pad to trace spacings on the coupons and potentially increase the size and/or complexity of the coupon? Steve Underwood Engineering Manager Circuit Center, Inc. 4738 Gateway Circle Kettering, Ohio 45440 937-435-2131 ext. 127 937-435-7698 fax [log in to unmask] ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################