If you have a battery-back up installed, pulling power will not force a reboot. There are two green LEDs on the switch, marked AC and DC. If you pull power, and the DC light stays lit, you have a battery back-up and nothing will have changed with the switch. If the DC light goes out, you've rebooted the system.

That said, what does no dial tone mean? No inside/intercom dial tone, no outside line dial tone or neither? Is the time and date correct on a display phone? If none of your phones are operating, a service call may be the only way to get back in business.

Sometimes the thoughts in my head get so bored, they go for a stroll through my mouth. This is rarely a good thing.