Service node for a telephony network

摘要

A service node provides a shared added value service within a telephony network, such as a public switch telephone network. Peripheral devices, such as speech applications platforms shared announcement platforms and message recording platforms, are connected to a switch which operates under the control of a central control computer. The switch includes distributed processors responsive to externally originating signals, such as DTMF signals, generated while calls are being processed. The distributed processing devices supply information derived form said signals to the central control computer. Thus, it is no longer necessary for a central control computer to examine ongoing calls in order to detect the presence of DTMF signalling. Detection of DTMF signalling is performed locally and information is returned back to the control computer only when relevant information has been detected. In this way, the size of the switch may be increased relative to the size of the control computer and the level of bandwidth required between the control computer and the switch is significantly reduced.