Sprint, AT&T, Verizon Sued Over Calling Card Patent
The suit, filed by inventor John R. Gammino, argues that the patent-in-suit is infringed when customers place phone calls using prepaid calling cards. The invention at issue provides telecommunications companies with a tool to selectively block and transmit international calls, the suit says.
Gammino claims his invention eliminated billions of dollars worth of potential losses by eradicating certain types of...
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