[Asterisk-Users] Failover Device?

[Matt]

First,
Something seems to be wrong with the list.  I'm not the only person
who has expressed seeing their messages either arrive late, or not at
all.

With that out of the way..

Is anyone aware of any type of failover device for PRI on asterisk? 
I've found the ISDNGuard, however it is currently not made in the
U.S., nor does it run on U.S. power.

Is anyone aware of a device that will detect (heartbeat?) if Asterisk
is running, and if not, failover to a backup server?