Olin,

On Fri, 20 May 2005 09:11:17 -0400, Olin Lathrop wrote:

> Alan B. Pearce wrote:
> > Well I did suggest that he put a triple row of holes down the edge to
> > fit a DIN 41419 style connector, and for those not using these you can
> > fit pin header strips up to 64 pins long, so with a double row you
> > could have 128 pins.
> >
> > My suggestion was for the PCB to be Eurocard size, but haven't seen any
> > comment on this.
> 
> I guess that's because I don't know what a DIN 41419 is, and don't know what
> size a "Eurocard" is, nor why that would be a desirable size.

Eurocard is 100 x 160mm, and the connector Alan is talking about is designed to fit on the end of it with 
connectors extending parallel to the board, making it into a plug-in card for rack mounting.  The standard 
allows for three rows of 32 pins (called A B and C) and any of them can be implemented - using A and C to give 
a 64-way connector is common.  Lots of rack mounting systems are designed to take Eurocards with the DIN 
connector to connect them to the backplane.  The first computer I built (Z80) used the technique, but with 
rather larger boards.

As for why it's a useful size, it's a nice aspect ratio, it's commonly used in Europe, Eagle's maximum size 
for the free and cheap versions is half a Eurocard, and Olimex's standard "single" PCB is one Eurocard.

I was going to post a link to a picture of the connectors, but Google can't seem to find them - I wonder if 
that number is right (it's a long time since I used it!).
 
> The board is basically built around the prototype area.  I'm currently
> thinking the board will be about 6" wide, which accomodates the 50 prototype
> columns with room for rubber feet or mounting holes.  Extra connector pads
> could fit in the extra width not used up by the mounting.

Well 160mm is pretty close to 6.3", and 100mm is just under 4", which sounds like a good size to me!

Cheers,


Howard Winter
St.Albans, England


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