Hi Larry, A plated-through hole (PTH) has a connector lead in it and is typically specified with a finished hole diameter to accept a lead diameter; a plated- through via (PTV) is typically much smaller in diameter and the hole should be specified as the drilled hole diameter (much more impotant for reliability assurance, and some small diameter PTVs can actually be plated closed). Other than that not much difference, however PTVs fail more often by interfacial separation (post separation) than due PTVs, which fail more often by barral fracture. Werner Engelmaier Engelmaier Associates, L.C. Electronic Packaging, Interconnection and Reliability Consulting 7 Jasmine Run Ormond Beach, FL 32174 USA Phone: 904-437-8747, Fax: 904-437-8737 E-mail: [log in to unmask] ################################################################ TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################