10 seconds you'll hear the phone ring. Lift the handset again and listen what the usually female voice says. Finally you dial the destination number which will originate in the USA also, taking advantage of this country's cheap overseas phone rates. Anyway these technicalities are all written in the documents sent by your callback provider. If you call many countries frequently as I do, using one callback service is no good deal.
Some countries are very cheap while others seem to be overpriced.
I use 4 services to get the most out of it. Of course there was no speed dial function yet, but a function that promised to use the callback service at a hotel in another country. Well, it was just a promise and never worked whether the hotel had a switchboard or not. Otherwise the system worked amazingly well, for prices that were much cheaper than KDD's rip-off fees. Over the following years many things have changed to the better or the worse.