Ok, I have a 3725 with 8 port ima card and 3620 with a ds3 card. I want to switch the two cards between the routers. I tried it once and failed. The cards came up and worked, but the router that now has the ima - the 3620 would no longer route the packets? I could not get to any of the remote connections from anything other than the 3620 itself. I know the link was working, because I could get to the other side, but again, only from that router.