We used lots of HAI 75A00-1 but when Leviton took over and released 75A00-2 we noticed a lot of them didnt work. Then Leviton discontinued the product and we moved on. But, we still have some systems we support and have needed to replace some card readers recently. We dug out some of the -2 units and they don't seem to drop in as a replacement. Was there something different about this model or it's wiring ?