Changing the battery is a non event. Back the system up, power down, remove the CPU, change the battery (CR2032) put the CPU back and power back on. I have never had to restore from back up as the system seems to be able to hold it's memory for the short time it takes to replace the battery, I take the back up just in case I get a 1st !

As for the no speech, I would be asking what changed in your network? Try doing a wireshark trace.