Pre-qualifying call-back service

DETAILED DESCRIPTION Service providers currently offer Call Back service to customers to make long-distance calls from a country that imposes high call tariffs more affordable.
The present invention may be better understood after a more detailed description of the prior art method for administering Call Back service.
Turning to FIG.
1, a prior art method for administering Call Back service is shown in block diagram form.
Suppose for the purposes of explanation that a customer located in Brazil wants to call a party located in the United States.
Suppose further that a call from Brazil to the United States costs $1.
50 per minute due to the tariffs imposed by the Brazilian government.
Also, suppose that a call from the United States to Brazil costs $0.
75 per minute due to the lower tariffs imposed by the U.
S.
government.
FIG.
1 illustrates the prior art method in which the Brazilian customer 102 would utilize Call Back service to call the Called Party 110 in the United States in a more affordable manner.
Customer 102 first places a telephone call to a call back server 106 located in the United States via a telephone utilizing a public switch telephone network ("PSTN"), as indicated in FIG.
1 by arrow 1.
Typically, call back server 106 will play a recording that prompts customer 102 to enter the telephone number from which he is calling on the telephone keypad.
Call back server 106 will recognize the dual tone multi-frequency ("DTMF") signals that are keyed from customer 102 then call back server 106 terminates its connection with customer 102 (i.
e.
, hangs up).
Call back server 106 then places a return call back to customer 102 via telephone over PSTN 108, as indicated in FIG.
1 by arrow 2.
Once a connection is established with customer 102 (i.
e.
, customer 102 answers the call from call back server 106), customer 102 begins being charged at the lower calling rate of $0.
75 per minute.
Call back server 106 may then prompt customer 102 to enter the United States telephone number that customer 102 wants to call on the telephone keypad