Thanks, I appreciate your replies.

Phone system is placed in night mode daily at 5:30pm. The reason we want to hear the phone ring while in night mode is: when someone is working after hours, they may choose to answer a call or they may be expecting a call.

When phone system was installed 6 years ago, the installer programmed a button on the operator phone so we only had to press that button to set night mode.

Since then, when night mode was set, we could hear the operator phone ring. I think this ring sounded different than the daytime ring.

This was the case until 2 weeks ago, when the operator phone stopped ringing when in night mode. When this was first noticed, I checked the ringer volume, that did not help.

I don't know if this is releated, but at that same time the receptionist was recording a new greeting, could she have pressed a sequence of buttons by accident that could have caused this?

Thanks