| 摘要 |
A communications system comprises a central unit (101) and terminals (102, 103, 104). It is equipped so as to establish and maintain a signalling connection between the central unit and at least one terminal using one of at least two alternative signalling protocols. To that end it comprises in the central unit means for indicating to a terminal the signalling protocols supported by the central unit, and means for setting up via the central unit's network interface a signalling connection between the central unit's signalling unit and the terminal, using a selected signalling protocol. Correspondingly, in the terminal the system comprises means for indicating to the central unit the signalling protocol supported by the terminal in response to a message sent by the central unit as well as means for setting up via the terminal's network interface a signalling connection between the terminal's signalling unit and the central unit, using a protocol supported by the terminal. <IMAGE> |
