If there is a need to disable ringing on the phone, this can be done by enabling the Do Not Disturb feature.

To Enable Do Not Disturb:

Pick up the phone and dial *78 then press Send. A recording will play advising the Do Not Disturb has been activated.

To Disable Do Not Disturb:

Pick up the phone and dial *79 then press Send. A recording will play advising the Do Not Disturb has been disactivated.