Synthetic ringback tone...?

[virtualmike]

Lately, I've noticed an interesting phenomenon when making calls from my Fusion line.

For about 60-70% of the calls I dial, I hear a ringback tone almost immediately after I hit the last digit. Even before the first cycle of that ringback tone has completed, I then hear a second ringback tone, usually at a different volume and/or pitch. That second ringback tone then cycles until the line is answered.

There's one number that I call that has an even odder situation. It's often busy (the person I'm calling is VERY busy). When I dial it, I hear a ringback tone for 1/2-3/4 second, then I hear the busy signal.

Does the Sonic.net switch generate a local ringback tone while the connection is being established, then the switch for the called number provides the ringback tone once the connection is complete?

This is similar behavior to what AT&T Wireless does when setting up incoming calls. A ringback tone is provided by the callee's home switch, and once the network locates the phone, the switch serving the area where the phone is located provides the ringback tone. I just hadn't encountered this before with landline phones.

I also encountered this with a former long distance company when I placed calls to the U.K. After dialing the call, I'd immediately hear an American ringback tone, instead of the usual British cadence. Except in that situation, the American ringback tone continued until the call was answered. Calling the same number from a different line (not subscribed to the same IXC) would get the British ringback tone.

[npatrick]

Our upstream providers return a message to us that says "the remote side is ringing" during call setup. This causes our equipment to begin generating a local ringback tone to the Fusion customer making the outbound call. Some of our upstreams begin sending audio shortly after this, and for most calls, this audio contains a ring tone produced by the remote end. These two ring tones can differ perceptibly in phase, cadence, amplitude, etc. This is the change that you're hearing.

In the case of that very busy individual, you're hearing that same locally-generated ringback tone for a brief period of time before the "this person is busy" message gets to us.

As you also pointed out, not all of our upstreams return this "early media" audio, especially in cases where the audio simply contains a ring tone. That's why this happens only some of the time.

Great question!

[virtualmike]

Thanks! I'm used to the way DMS100s and 5Es and 1EAs handle this.

[virtualmike]

There's one number that I call that has an even odder situation. It's often busy (the person I'm calling is VERY busy). When I dial it, I hear a ringback tone for 1/2-3/4 second, then I hear the busy signal.

Within the last week, I started getting similar, and probably related, behavior when calling that number from my cell phone.

At least five times, I've dialed the number from my cell, received two cycles of ringback, and then been disconnected (instead of connected to the busy signal bus). Upon checking with my friend, I learned that she'd been on the phone during that time.

If it helps to know, the number I'm calling is on Verizon's PDRYCAXF82A switch, which appears to be a 5E, according to my sources.