You may have your call recording on (just a guess). When on, it will give a tone to remind people the call is being recorded. If you're not sure, or want to turn off call recording, Go on-line to your Admin Portal and click on Auto Receptionist under phone system. From there click on call recording. There are 2 settings: One for on-demand and one for automatic. If I'm correct (again, just a guess), I'd bet you are set for automatic call recording. In any event, you can click on that, and if call recording is not important to you you can check disable and save. If it is important to you and is already enabled, uncheck the offending box just under the "enabled" and disabled" selections titled "play periodic tones for outbound calls". If that box is checked it will play the tones you are speaking of. If this is not the issue, I'd have to think about it some more but that's the only thing I can think of that would cause the tone.