Patent ID: 7907715

Claim:
A method of blocking a telephone call from a calling party to a called party, comprising: receiving a telephone call from the calling party at a local-designated trunk group of a service switching point (SSP) serving the called party; determining, based on redirection information contained in a redirection field of an Info_Collected query message associated with the telephone call sent to the service control point, if the Local and Access Transport Area (LATA) of the calling party is interLATA with respect to the SSP, wherein the SSP is within an SSP LATA; and when the calling party is interLATA with respect to the SSP, determining a screening indicator value, wherein the screening indicator value comprises a value of a field, other than the redirection field, in the Info_Collect query message, wherein the screening indicator value indicates whether the telephone call has been transmitted at least in part using a private network, and blocking the telephone call when the screening indicator value indicates that the telephone call has been transmitted at least in part using a private network.