-- [ From: Doug Jeffery * EMC.Ver #2.10P ] -- Hi, I have been looking in IPC-D-275 and RB-276 for design criteria for a TDR coupon. I could only find a reference to IPC-D-317..Which, of course, I do not have.(had to order).. Does anyone know if this spec. has the coupon construction information (number of holes, recommended sizes, which holes hook to power/ground/signal for the varieties of Impedance styles? Is there a standard coupon, or does everyone make their own as they go? Thanks, Doug Jeffery Electrotek, Inc. [log in to unmask] (414)762-1390