We have two Asterisk servers. One is a warm failover (ie, we have to make it work manually should the first one fail, but it gets regular configuration updates so it's always ready to be made live) and the other is the live server. They both have Digium Wildcard TE405P's in them, and the hardware and software is otherwise identical, but the last time we needed to use the failover server, things went poorly when it was plugged into the PRI line. Now, we're upgrading the failover box to Asterisk 1.6 and pressing it into service.
I really need a way of thoroughly testing (including testing under load) the TE405 hardware and configuration before we need it. I can't just set up and tear down a PRI line for testing for an hour or a day, and the expense of the line prevents us from having a complete backup. Likewise, just switching the cable from one server to the next is also highly disruptive.