The cost of US Telephoney is 2.3 Cents Per Minute within the RBOC USA. The cost of Calling to UK and Europe is 3.5 Cents per minute. Safely if you can offer minimum billig committment to the carrier in USA then the rates are on sliding scale. The cost of PSTN ( US End ) fro CO-Lo hovers between 1.4 – 1.7 Dollars per Hour Per Agent. I hope you have understood the Calculations. Need more info, write again