I have the Partner ACS-R7 system. Occasionaly when a call is answered at say extension 11 using speakerphone and then put on hold, then go to a different floor for extension 14 and continue the call, extension 11 will time out and go hi/low loudly because the speaker button is still on. I assume this is because the call began as a speakerphone call and then the hold button was pressed. In this installation, a phone off hook is not a problem. The warning tone IS a problem. Can it be eliminated entirely?