"With the phone in standby, press and hold # on any handset. The phone prompts you to select the number of hours (1 - 9 or Always On) that you want it to stay in silent mode. To confirm press # or wait 5 seconds.
Each handset will display silent mode.
The phone will exit silent mode after the set number of hour or to exit manually press and hold # again."
I was having problems turning off the mute on my mom's Panasonic cordless phone. I cracked the code by holding down the “0” button. You will notice that it has a bell with a line through it. Once you hold it for a few seconds it gives you the option to unmute. Once you unmute, it will immediately go to snooze “ZZzz.” You can then go to Menu and adjust the volume. Whewww…It took me a while to figure it out. I hope this helps.