modular panel standard??

[Terry Michaels]

Message text written by Nick Zuccaro
>i was also wondering if anyone uses edge-card connectors, and
how they work out. i'm not real familiar with them, but they
look like a pretty nice circuit connection and also mechanical
suport. i've kicked around gutting old computer motherboards for
the isa connectors, but i don't know if a home-etch board would
mount good to these.<

Hi Nick:

Edge card connectors work well if they are done right.  I have used them in
production of a lot of different products going back a number of years.  If
you etch a single sided circuit card, maybe tin plated, with, say, a 22 pin
edge connector, with a contact spacing of 0.156", you will find it will
work well initially, but after some period of time, a year or several
years, you will often have some circuit cards that will not maintain a good
connection, and you will have to wiggle the connectors around to get them
to work. 

The best approach is to etch a double sided card, with the contact fingers
on each side tied together with vias, and preferably gold plated.  This
becomes more important if you go to 0.125" or 0.100" contact finger
spacing.

One drawback to edge connectors is you have to notch out around the edge
connector area out of what would otherwise be a simple rectangular PC
board.

Terry Michaels