A SYSTEM FOR AUTOMATICALLY SWITCHING BETWEEN ANALOGUE AND IP TELEPHONY

Abstract: 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.

Description: A system for automatically switching between analoque and IP telephony. The present invention relates to a system for automatically switching between analogue telephony and IP telephony, customer apparatus incorporating the system, an adapter card for implementing the system suitable for insertion in a PC, a PC incorporating the adapter card and a method of switching between analogue and IP telephony. At the present time, two different kinds of telephony are used, the regular old circuit switched telephony and the new IP telephony. Homes can now be connected both to the PSTN network and to an IP telephony network at the same time. It would he advantageous if the existing analogue telephones, with which everyone is familiar, could be used to handle both kinds of telephony. Ideally, a system for use of both IP telephony and switched circuit analogue telephony should automatically switch between IP and circuit switched telephony, i.e. there should be no need for manual switching between regular ( telephony and IP telephony. Preferably the switching should employ a software implementation. The present invention achieves a solution to the problem presented above, by using a dialled prefix digit to switch from a preselected form of telephony, e.g. circuit switched telephony, to the other form of telephony, e.g. IP telephony. The invention may be used in media gateways between the PSTN and IP network, or in hosts which are connected to both of these networks. . The present invention facilitates the provision of a more robust telephony service with the possibility of adding innovative new services. The invention also results in a saving of bandwidth and enhanced user friendliness, both of which are of considerable economical benefit. Systems which manually switch between analogue switched circuit telephony and IP telephony are known, e.g. switching is achieved by clicking an appropriate icon displayed on a PC VDU. However, a solution in which s witching is initiated from the telephone handset is believed to be new and to give very substantial advantages to users who may be unfamiliar with the use of PCs. The present invention has the following advantages: reliability: the IP network can be used for phone and other IP-based services while the phone service can also use the circuit switched network if there is congestion in the IP network; furthermore, in the case of power failure the circuit switched network will automatically be connected; user friendliness: existing analog telephones, both the ordinary and wireless DECT telephones, can be used in a way familiar to the user and still enable the user to take advantage of the new IP telephony technology to make cheaper long distance calls; bandwidth saving: the phone service is converted to IP telephony at the earliest stage in the network, thereby saving bandwidth; apd flexible value added service additions: the invention facilitates the addition of new services, e.g. a common phone answering service for regular telephony and IP telephony. According to a first aspect of the present invention, there is provided a system for switching an analogue telephone, or telephone network, between an IP connection and a CSN connection, characterised in that switching means are provided to automatically connect said analogue telephone, or telephone network, to a default connection in the absence of a switching signal initiated from a telephone handset, in that detection and control means are provided to detect said switching signal and, on detection of said switching signal, to actuate said switching means to connect said analogue telephone, or telephone network, to a non-default connection. Said default connection may be a connection to the CSN and said non- default connection may be a connection to said IP network. Said switching signal may be a dialled prefix digit. Power failure means may be provided adapted to detect a power failure and, on detection of a power failure, to connect said analogue telephone, or telephone network, to said CSN. Said switching means may be software controlled. Said detection and control means and said power failure means may be implemented on an adapter card located in a PC. Said IP connection may be an ISDN connection. Said IP connection may be an ADSL connection. Said IP connection may be realised over an optical fibre. Said telephone network may include a plurality of subscriber equipments. Said system may be adapted for installation in residential premises. Said system may be adapted to act as a switch between a PSTN and a LAN. According to a second aspect of the present invention, there is provided customer apparatus, characterised in that said apparatus incorporates a system as set forth in any previous paragraph. According to a third aspect of the present invention, there may be provided an adapter card comprising detection and control means adapted to detect a switching signal originating from a telephone and, on detection of said switching signal, adapted to actuate switching means to connect an analogue telephone, or telephone network, to a non-default connection. Said switching signal may be a dialled prefix digit. Said default connection may be a connection to the CSN and said non- default connection is a connection to said IP network. Power failure means may be provided adapted to detect a power failure and, on detection of a power failure, to connect said analogue telephone, or telephone network, to said CSN. A CSN gateway means and a terminal adapter means may be provided. Said detection and control means may be implemented in software. According to a fourth aspect of the present invention, there is provided a PC, characterised in that said PC incorporates an adapter card as set forth in any previous paragraph. According to a fifth aspect of the present invention, there is provided a method of switching an analogue telephone, or telephone network, between an IP connection and a CSN connection, characterised by automatically connecting said analogue telephone, or telephone network, to a default connection in the absence of a switching signal originating from a telephone, and by actuating a switch, on detection of said switching signal, to connect said analogue telephone, or telephone network, to a non-default connection. Said default connection may be a connection to the CSN and said non- default connection may be a connection to said IP network. Said switching signal may be a dialled prefix digit. On detection of a power failure, said analogue telephone, or telephone network, may be connected to said CSN. Said IP connection may be an ISDN connection. Said IP connection may be an ADSL connection. Said IP connection may be realised over an optical fibre. Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 schematically illustrates the system of the present invention. Figure 2 illustrates an adapter card according to the present invention. To assist in the understanding of the present invention a glossary of the abbreviations used in the present invention is set out below: ASDL: Asynchronous Subscriber Digital Line CSN: Circuit Switched Network GW: GateWay IP: Internet Protocol ISDN: Integrated Services Digital Network LAN: Local Area Network PC: Personal Computer PSTN: Public Switched Telephone Network TA: Terminal Adapter A telecommunications subscriber who has access to both regular switched circuit telephony and IP telephony, i.e. has an ISDN, ADSL, or an optical fibre, connection to the public network and, at the same time maintains a PSTN connection, should be enabled to use his analogue telephones for both kinds of telephony. A system, according to the present invention, for facilitating this is illustrated in Figure 1. The system is essentially a residential gateway to which both the CSN, IP network and home network are connected. Analogue telephones form part of the home network which may, inter alia, include a PC, fax machine and other subscriber apparatus. The residential gateway includes an adapter card which may, for convenience, be located in a PC, i.e. in a Residential Gateway. The adapter card is illustrated schematically in Figure 2. The adapter card includes a gateway, GW, to the CSN, a terminal adapter TA and a software switch to enable either the CSN, or the IP network to be linked directly to the home telephony network. A power failure relay is also provided to automatically connect the home telephony network to the CSN in the event of a power failure. Switching between the CSN and IP network is performed automatically and is totally software controlled. When receiving calls, the call which is received first is the one that is accepted. When making calls, the preferred type of telephony, i.e. the type of telephony normally used by the subscriber, is the system default. To employ the other type of telephony, i.e. not the default telephony, a prefix digit is used. For example, if CSN telephony is the default, dialling a telephone number will result in a connection being made via the PSTN. However, if a prefix digit is dialled, e.g. "9", the connection will be established via IP telephony and the adapter will perform all the necessary conversion functions required by the IP. In the case of a power failure the analogue telephone(s) are automatically connected directly to the circuit switched network by the power failure relay. Though not shown in the drawings, the gateway can also be used as a gateway between the circuit switched network and the IP network, but only for a single call. The system of the present invention can be used: in a Residential Gateway between a home network and a public network; and - In company networks as a flexible switch between the PSTN and a LAN. As previously explained the present invention has the following advantages: reliability; user friendliness; - bandwidth saving; and facilitates provision of new services.

Claims: CLAIMS 1. A system for switching an analogue telephone, or telephone network, between an IP connection and a CSN connection, characterised in that switching means are provided to automatically connect said analogue telephone, or telephone network, in that detection and control means are provided to detect a switching signal and to actuate said switching means to connect said analogue telephone, or telephone network, to a connection. 2. A system, as claimed in claim 1 , characterised in that a default connection, is initiated, in the absence of the switching signal, initiated from a telephone handset, and on detection of a switching signal, to actuate said switching means to connect said analogue telephone, or telephone network, to a non-default connection. 3. A system, as claimed in claim 2, characterised in | that said default connection is a connection to the CSN and said non-default connection is a connection to said IP network. 4. A system, as claimed in either claim 2, or claim 3, characterised in that said switching signal is a dialled prefix digit. 5. A system, as claimed in any previous claim, characterised in that power failure means are provided adapted to detect a power failure and, on detection of a power failure, to connect said analogue telephone, or telephone network, to said CSN. 6. A system, as claimed in any previous claim, characterised in that said switching means is software controlled. 7. A system, as claimed in any previous claim, characterised in that said detection and control means and said power failure means are implemented in a PC. 8. A system, as claimed in any previous claim, characterised in that said IP connection is an ISDN connection. 9. A system, as claimed in any of claims 1 to 7, characterised in that said IP connection is an ADSL connection. 10. A system, as claimed in any of claims 1 to 7, characterised in that said IP connection is realised over an optical fibre. 11. A system, as aimed in any previous claim, characterised in that said telephone network includes a plurality of subscriber equipments. 12. A system, as claimed in any previous claim, characterised in that said system is adapted for installation in residential premises. 13. A system as claimed in any of claims 1 to 11, characterised in that said system is adapted to act as a switch between a PSTN and a LAN. 14. Customer apparatus, characterised in that said apparatus incorporates a system as claimed in any of claims 1 to 12. 15. An adapter card for use with a system as claimed in any of claims 1 to 13, characterised in that said card includes detection and control means for detecting a switching signal originating from a telephone and, on detection of said switching signal, to actuate switching means to connect an analogue telephone, or telephone network, to a non-default connection. 16. An adapter card, as claimed in claim 15, characterised in that said switching signal is a dialled prefix digit. 17. A adapter card, as claimed in either claim 15, or claim 16, characterised in that said default connection is a connection to the CSN and said non-default connection is a connection to said IP network. 18. An adapter card, as claimed in any of claims 15, to 17, characterised in that power failure means are provided adapted to detect a power failure and, on detection of a power failure, to connect said analogue telephone, or telephone network, to said CSN. 19. An adapter card, as claimed in any of claims 15 to 18, characterised in that there is provided a CSN gateway means and a terminal adapter means. 20. An adapter card, as claimed in any of claims 15 to 19, characterised in that said detection and control means are implemented in software. 21. A PC, characterised in that said PC incorporates an adapter card as claimed in any of claims 15 to 20. 22. A method of switching an analogue telephone, or telephone network, between an IP connection and a CSN connection, characterised by automatically connecting said analogue telephone, or telephone network, by actuating a switch, on detection of said switching signal, to connect said analogue telephone, or telephone network, a connection. 23. A method, as claimed in claim 22, characterised by a default connection being a connection to the CSN and a non-default connection being a connection to said IP network. 24. A method, as claimed in either claim 22, or claim 23, characterised by said switching signal being a dialled prefix digit. 25. A method, as claimed in any of claims 22-24, characterised by automatic connecting said analogue telephone, or telephone network to the default connection in the absence of the switching signal, originating from a telephone handset, and on detection of a switching signal, to connect said analogue telephone, or telephone network, to the non-default connection. 26. A method, as claimed in any of claims 22, to 25, characterised by, on detection of a power failure, connecting said analogue telephone, or telephone network, to said CSN. 27. A method, as claimed in any of claims 22 to 26, characterised by said IP connection being an ISDN connection. 28. A method, as claimed in any of claims 22 to 26, characterised by said IP connection being an ADSL connection. 29. A method, as claimed in any of claims 22 to 26, characterised by said IP connection being realised over an optical fibre.

Inventors: WILHELMSSON LENNART, WILHELMSSON, LENNART
Applicants: TELIA AB
Application year: 2000
Main classification: H04M3
IPC codes: H04L29, H04M1, H04M7