| 摘要 |
A voice traffic gateway (10) comprising a voice traffic input (12), a voice traffic output (14), a first domain router (16), non-secure warning (NSW) tone application apparatus (18) and a signalling filter (20). The input (12) receives voice traffic comprising voice messages and signalling messages from a first traffic domain. The output (14) delivers output voice messages and signalling messages to a second, different traffic domain. The first domain router (16) routes voice messages to the NSW apparatus (18) and routes signalling messages to the signalling filter (20). The NSW apparatus (18) applies a NSW tone to a received voice message to form an output voice message. The signalling filter (20) compares a feature of a received signalling message with a reference feature. The signalling filter (20) will pass a signalling message if the signalling message feature is the same as the reference feature and will block a signalling message if the signalling message feature is not the same as the reference feature. |
