| 摘要 |
A voice traffic gateway including: a voice traffic input, a voice traffic output, a first domain router, non-secure warning (NSW) tone application apparatus and a signalling filter. The input receives voice traffic including voice messages and signalling messages from a first traffic domain. The output delivers output voice messages and signalling messages to a second, different traffic domain. The first domain router routes voice messages to the NSW apparatus and routes signalling messages to the signalling filter. The NSW apparatus applies a NSW tone to a received voice message to form an output voice message. The signalling filter compares a feature of a received signalling message with a reference feature. The signalling filter 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. |
