| 摘要 |
<p>The invention is a system for switching an analogue telephone, or telephone network, between an IP connection and a CSN connection. A switch is set to automatically connect the analogue telephone, or telephone network, to a default connection in the absence of a switching signal initiated from a telephone handset. If an appropriate switching signal is detected the switch connects the analogue telephone, or telephone network, to a non-default connection. Typically the default connection is the circuit switched network and the non-default connection is the IP network. The switching signal may be a dialled prefix digit. A power failure relay may be provided to detect a power failure and, on detection of a power failure, to connect the analogue telephone, or telephone network, to the circuit switched network.</p> |
