Ringback Tones - Explain Them To Me

So just what are Ringback Tones? In simple terms, when you call someone you usually will hear a beep letting you know that you have been connected and the phone is ringing - this is the ringback tone.Another way to explain it is that it is a status indication that the number dialed is available (ie in service and not busy).  This requires that the proper connections through the relevant telephony network or networks between the caller and the callee's audio devices are either made, or are available to be made, and the phone call will be connected if the call is picked up - either by an answering service or a person. Once the receiving party has either answered your call, or you call was picked up by an answering machine or network voice service, the ringback tone stops. (awwww). The actual sound of a ringback tone will depend on your country and/or carrier.  Again, if we want to get technical, in North America (United States and Canada), which are within the North American Numbering Plan (NANP), the standard PSTN ringback tone is generated by summing a 440-Hz tone with a 480-Hz tone and applying these to the telephone line in a two-second on and four-second off pattern.The tone combination produces a warbling "ring ... ring ... ring" sound, caused by the 40-Hz beat, or interference due to the difference in frequency, between the two tones. The ringback tone may be generated by the switch serving either the called party or the calling party, but it is not generated by the called telephone instrument or PBX. The ringback tone generally starts and stops at the same rate as the ringing tone of the called telephone, but generally is out of phase, i.e., staggered in time. Finally we get to the fun part about ringback tones - rather than the standard 'ring ring' tone we just talked about above, cellphone carriers have made it possible to personalize the ringback tone that your cellphone service will play when a caller is waiting for you or your machine to pickup. A huge selection of current (as well as classic) music and audio clips are available for selection on your cellphone to play as the ringback tone.  Customizing your ringback tones in this manner is available through subscription services with your particular carrier, and is generally billed as an additional charge per tone selected. Now here is the best part - you can completely customize the ringback tones that your callers hear.  What's even cooler is that you can choose a ringback to suit each individual caller.  Generally, you can pick up to around 100 ringback tones at any given time.  Each one of these can be setup so that each of your callers hear different ring back tones.  The other method of setting them up is to choose a tone to suit the time of day.  This is most often used so that callers hear a 'work hours' and a 'non-work hours' ringback tone.For more information about customizing your cellphone service to play ringback tones you can often find the menu commands with a  websearch for your cellphone carrier and 'ringback tones'.