Hi Doug - This may seem to be a trivial point but the JSTD-001 committee spent considerable time (I mean a bunch!) on the discussion of "high reliability' versus "high performance" as a descriptor. We all want our electronics to be very reliable whether its on a F-16, a 1997 Chevy or my boy's Teddy Ruxpin toy. There is a natural tendency to look at a specification's classifications and pick the "high reliability" choice because of one's impressions about that descriptor seems to indicate rather than looking at what one's use environment really demands. That's why in JSTD-001 there is General electronics, Dedicated electronics, and High performance electronics with descriptions of each. We probably should petition Dave Bergman to see about getting this philosophy discussed as something for all the specifications within the IPC system. Ok, now I'll go get a Coke and get off my soapbox. Dave Hillman Rockwell Collins [log in to unmask] ______________________________ Reply Separator _________________________________ Subject: Re: IPC-SM-840 Author: [log in to unmask] at ccmgw1 Date: 1/31/97 11:54 PM LaVern, In the C rev of SM-840, we went away from the usual class 1,2,3 of IPC convention and went to a class H (for high reliability) and class T (for telecommunications). T - Telecommunications (includeds computers, telecommunication equipment, sophisticated business machines, instruments, and certain non-critical military applications). Solder mask on boards in this class is suitable for high performance commercial and industrial products in which extended performance life is required, but for which interrupted service is not life threatening. H - High Reliability / Military (includes that equipment where continued performance is critical, equipment down-time cannot be tolerated and / or the equipment is a life support item). Solder mask on boards of this class is suitable for applications where high levels of assurance are required and uninterrupted service is essential. Note: Class Designations - Previous versions of this specification, and other IPC documents, make reference to Class 1, Class 2, and Class 3. For all practical purposes, there is no Class 1 solder mask. Class 2 is equivalent to Class T. Class 3 is the equivalent of Class H. If you would like more information, please contact me. Doug Pauls Vice-Chair Solder Mask Task Grou CSL [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************