I believe the context of the message you refer to is considered 'a joke.'
> -----Original Message----- > From: JaMi Smith [mailto:[EMAIL PROTECTED]] > Sent: Friday, October 11, 2002 10:40 PM > To: Protel EDA Forum > Cc: JaMi Smith > Subject: Re: [PEDA] flipping board > > > I am not quite sure of what the context of this statement is, > since the thread took a rather twisting road to get to this > point, and I could not quite follow it, so I will just > comment on the statements below just as they stand, and hope > that it is not too far out of context. > > According to IPC, the top side of the PCB is the is the > "Primary Side" of the PCB, which generally corresponds to > what we used to call the "Component Side", and the bottom > side of the PCB is the "Secondary Side" of the PCB, which > generally corresponds to what we used to call the "Circuit Side". > > The "Primary Side" of the PCB us usually chosen or selected > by the Designer for some distinctive reason, such as being > the side with the most components, or most complex features, > etc., but this is not necessarily so, and there may be no > other reason beyond the Designers preference for this side > being chosen as the "Primary Side" of the board.. > > Physical Layers of the PCB are numbered beginning from the > "Primary Side" (top layer) being numbered as Layer 1, and > counting down sequentially thru the board to the "Secondary > Side" (bottom layer), and then continuing with Solder Mask > (Top, then Bottom), and then Silkscreen (or "overlay") (also > Top then Bottom), etc., etc.. > > The PCB also is usually demensionally defined as having three > mutually perpendicular datum planes. The first of these is > called the "Primary Datum", and is defined as being the > "Bottom Side" (or "Back Side"), of the PCB, or I suppose one > could say that it is the theoretical plane upon which the PCB > is said to rest. > > This sometimes leads to confusion, because the "Top Side" of > the PCB is the "Primary Side" of the PCB, but the "Botton > Side" (or "Back Side") of the PCB is the "Primary Datum > Plane" of the PCB. > > For further confusion on the subject, see IPC-2221 Generic > Standard on Printed Board Design, Sections 5.4.3 Datum > Features, and 11.2.1 Viewing (which will refer you to IPC-D-310). > > JaMi > > ----- Original Message ----- > From: "Michael Reagan (EDSI)" <[EMAIL PROTECTED]> > To: "Protel EDA Forum" <[EMAIL PROTECTED]> > Sent: Thursday, October 10, 2002 12:22 PM > Subject: Re: [PEDA] flipping board > > > > The only thing left now is Jun is now producing a design > counter to IPC > > guidelines for documentation, Primary side is on the bottom. > > > > > > > * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://firstname.lastname@example.org * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *