Do not know how to turn off the slient mode - Uniden Lands Phones

You can silence the ringers on the base and handsets at the same time. It doesn't affect the visual ringer on the phone in standby, press and hold Silent on the base. The phone automatically turns on the answering system and shows Do Not Disturb in the display on handset. (The answering system answers any incoming calls without playing anything through the speaker.)To cancel, press Silent again. If you turn the answering system off while Silent Mode is on, the phone turns off Silent Mode.

• You didn't mention your model# Below is for the Uniden(D1660)
• After the selected number of hours, the phone automatically exits silent
  mode. To exit silent mode manually, press and hold # again.
  If the phone is in silent mode and you turn off the answering
  system, the phone exits silent mode