[startledmarmot]

It really boils down to money. When the call connects, somebody gets charged. Perhaps both of you do -- you lose a minute on your cellphone bill, and the school gets charged a minute for the phone call.

Putting the school notice in the RBT space eliminates this charge and essentially makes the entire transaction "free."

Lots of big companies use this for the first step in their automated attendants. Since DTMF (phone number signals) are transmitted during the ringback tone (but voice is not), they can put the first step of their attendant in the RBT space. This saves them the money if you never get any further, or decide to hang up soon after.

[josh2600]

The settlement agreements for calls are pretty straightforward (Sending party pays). Consumers are also billed for service, but behind the scenes there's a wholesale market where traffic imbalances are valuable (this is also a core issue with Net Neutrality; consider that at peak Netflix is 35% of global bandwidth which is mostly delivered by one provider: cogent).

There's a whole different discussion around signaling and abusing both headers and early media transfers to avoid billing. It's still very largely the wild west, IMHO.

[startledmarmot]

Truthfully, regarding call connect charges, ringback, per-minute fees, etc... I don't think many folks think much about the fact that a lot of the business and billing decisions driving modern telecom policy are still rooted in the same thought patterns they were in the 1950s. It drives the net neutrality debates, it drives shareholder profit expectations, everything.

And I agree - it's absolutely the wild west. After 70 years of doing it one way, we're starting to see a tipping point of new realtime infrastructures and technologies. Unfortunately, I think it's likely to become even more wild as the "silo-ification of communication" trend continues. Boo.

Don't get me started on credit card processing fees. ;)