A helpful feature that is built into the TrackR app is the ability for your TrackR to ring your phone by simply pressing the button on your TrackR. However, if you are disconnected from your phone's Bluetooth (either out of range or it is turned off) or if the TrackR app has been forced closed, then you will hear the TrackR make a two-toned beep, one high and one low when the button is pressed. Once you are back within Bluetooth range or Bluetooth is turned back on, you will be able to ring your phone by pressing the TrackRs button.
While being out of range is the most common reason for your TrackR to give you the two-tone beep, it can also occur when trying to pair your TrackR with a new phone. Luckily, this issue is easily solved by simply removing the battery and re-inserting the battery. This will reset the TrackR so it will properly connect.
Please view this article for instructions on resetting your TrackR.