To all: Controlled Impedance products are becoming more and more popular. I am interesting in hearing opinions on the relevancy of the TM-650 standard for controlled impedance testing. How many people our using it and if not should it be changed? Sincerely, Brian Butler Introbotics Corp (505)345-7785 www.introbotics.com The reference website link information for the IPC Standards Document IPC-TM-650 Test Method 2.5.5.7 Characteristic Impedance and Time Delay of Lines on Printed Boards by TDR, is: www.ipc.org/html/fsresources.htm Select "IPC Documents Available for Download IPC standards and manuals that may be downloaded for free. " from the bottom of the page... And then select "2.5.5.7” from the list of documents Specific reference to section: 4.1 Instrumentation