RCav8or: I can't testify to the Honeywell 406 ELT. On the Artex they use ships power to flash a light on the flight deck if the ELT is transmitting as a warning to the pilot it is going off.
boguing: The ELT is always powered by it's internal battery. It can be set to transmit by the remote switch on the flight deck, or by impact if the G switch has been activated. (you've crashed or had a really bad landing)
We want the ELT to work, and continue transmitting even if all ships power is lost, so we can find the downed aircraft.