I sent this message to TechNet on 08/10/2000. Did this message make it to the list? I did not get any responses. :-) 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 ############################################################## 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 ##############################################################