Hi Steve..

It appears Concord was purchased by Savaria Elevator. You might check out Savaria site and see if anything's still supported over there for Concord.

http://www.savaria.com/products/home-elevators/index.php

If it's just a relay control, you can probably use the diagram and wire new buttons to the control. You can have a COP probably made at a local fab shop, purchase some 3rd party vendor buttons and wire it in to the control..

If it's a processor control the buttons are probably still discreet and you can do the same thing. I doubt Concord used any kind of serial link from the buttons to the control..

Good luck.

It Don't mean a thing if it aint got that swing.

Cool, Free, Johnny Smith courtesy of NPR..HERE
http://www.npr.org/ramfiles/asc/asc25.smith.asx