PROCEDURE AND SYSTEM FOR TRANSMITTING AN EMERGENCY CALL IN THE EVENT OF MALFUNCTION IN THE TELEPHONE NETWORK

Abstract: The invention relates to a procedure and a system for the re-routing of emergency calls in the event of a failure in the telephone network. According to the invention, emergency calls are directed in a concentrator to an emergency line and directed further to a regional fire brigade control centre via a mobile station connected to the emergency line. In the system of the invention, no delay occurs in the re-routing and further routing of emergency calls in the event of failure of the telephone network.

Description: PROCEDURE AND SYSTEM FOR TRANSMITTING AN EMERGENCY CALL IN THE EVENT OF MALFUNCTION IN THE TELEPHONE NETWORK The present invention relates to a procedure as defined in the preamble of claim 1 for the rerouting of emergency calls from a telephone exchange or concentrator in a wired telephone network in a failure situation, which may arise when the links between telephone exchanges or the higher telephone exchange is inoperative. When the interconnecting lines or the higher telephone exchange (i.e. the telephone exchange to which the telephone exchange or concentrator with which the subscriber is communicating is connected) fails, the internal traffic in the telephone exchange or concentrator still works normally. In such a situation, emergency communication is directed to a given subscriber line connected in conjunction with the telephone exchange or concentrator. Having received no- tice of the malfunction in the telephone network, the operator sends the Regional Fire Brigade Control Centre (RFBCC) information as stipulated (12.4.1995) by the Telecommunications Administration Centre about the situation if the expected duration of the disturbance exceeds 30 minutes and the number of disabled subscriber lines exceeds one hundred. Having received this information, the RFBCC sends e.g. a municipal fire service unit to the exchange for emergency communication service. The crew of this unit establishes a te- lephone connection with the subscriber line in the telephone exchange or concentrator to which emergency calls are directed, receives any emergency calls and connects them further to the RFBCC via a fire service wireless network. In the present situation, the problem is that the transmission of emergency calls may be delayed due to human factors. Passing the information from the operator's control room to the RFBCC takes minutes. In areas where there is no regular fire brigade in continuous readiness at a fire station, the delay before readiness for departure of the fire brigade is five minutes, in other words, it takes five minutes from the alarm given by the RFBCC before the fire brigade is ready to depart. The emergency vehicle travels at a speed of about 1 km/min in emergency service. It de- pends largely on the people on duty in the chain how much time elapses from the detection of a cable breakdown or other failure to the moment when the exchange is ready for telephone answering service: how quickly the person on duty in the operator' s answering service informs the RFBCC, whether the RFBCC gives the commission to the fire brigade as an urgent emergency order, and so on. In a case where the exchange is located at distance of 10 km from the fire station, this delay is at least about 20 minutes, but it can easily become even half an hour or more. The object of the present invention is to eliminate the problems described above. A specific object of the invention is to present a procedure and a system for directing emergency calls to a regional fi- re brigade control centre without manual switching by human labour. A further object of the invention is to present a system for re-routing emergency calls without delay in the event of malfunction in the telephone network, a system that always works regardless of the duration or extent of the malfunction. The procedure of the present invention for ensuring emergency calls is applicable in a telephone network comprising a number of telephone exchanges and interconnecting lines for the setup of connections between the telephone exchanges. Moreover, connected to the telephone exchange are a number of terminal devices used to set up calls or data connections via the telephone network. Further, in the procedure of the invention, in a situation that may arise when there is a fault in the higher exchange or in the interconnecting line leading to it, an emergency call received at the telephone exchange is directed to a subscriber line connected to the telephone exchange for emergency calls. The telephone exchange may also comprise an access node, via which subscribers in a local loop are connected to the telephone exchange. A subscriber line for emergency calls can be connected to the access node as well. According to the invention, a mobile station is connected to the subscriber line for emergency calls and the emergency call is passed on from the subscriber line by means of the mobile station. The mobile station may be one working in any mobile communication network, such as the GSM network (Group Special Mobile) , NMT network (Nordic Mobile Telephone) , ARP network (car radiotelephone) or in a corresponding network. The use of network other than the GSM network may be appropriate in remote districts where no GSM coverage exists; in respect of coverage area, the ARP and NMT networks are still better than the GSM network. As compared with prior art, the present invention has the advantage that the system of the invention involves no delay in the re-routing and further routing of emergency calls in the event of failure of the telephone network. The only drawback is conges- tion, because only one subscriber at a time can call an emergency number, but this is the case even when a fire service unit transmits the calls by radio. On the other hand, congestion can be reduced by adding extra subscriber lines to the concentrator for emergency communication. Another advantage of the invention as compared with prior art is that it makes it possible to leave out one human factor, i.e. one operator, who may delay or distort the emergency call or even fail to pass on the message at all, from the link between the person making an emergency call and the person on duty in the RFBCC answering service. A further advantage of the present invention is that emergency communication is ensured even during short disturbances, which at present do not require any special measures at all. Moreover, the operator will have more time to inform the RFBCC about disturbances . In addition, the system of the invention has the advantages of being simple and cheap and that it can be implemented by combining existing equipment and properties. Furthermore, the invention makes it unnecessary for the fire service to engage personnel and equipment in telephone answering duties. In an embodiment of the invention, the mobile station is connected to the subscriber line for eraer- gency calls via an adapter. The functions of the adapter are to carry out the dialling in the mobile station and, after that, connect the emergency call wanted by the subscriber to the mobile station. In the telephone exchange, the emergency call is preferably connected in steps as follows. First, the telephone exchange receives the dialling for the emergency call and, based on this, in the event of failure of the telephone network, the call received at the telephone exchange is connected to the adapter. Next, by means of the adapter, the number for the emergency call is dialled and the call is connected to the mobile station. The mobile station can preferably be provided with a directional antenna, which is used to improve reception in the mobile station. In an embodiment of the invention, the number dialled by the subscriber in a failure situation is monitored in the telephone exchange and, based on this monitoring, call setup via the subscriber line connected for emergency calls is disabled if it is found that the connection is intended for a call other than an emergency call. In this way, emergency calls can be switched in a failure situation as effectively as possible. The emergency call can be an automatic alarm message, an alarm call or the like. The system of the invention for ensuring emergency communication in a telephone network compri- sing a number of telephone exchanges, to which is connected a subscriber line for emergency calls, the links between which are implemented using interconnecting lines and to which are connected a number of terminal devices used to set up calls or data connections via the telephone network, comprises an arrangement whereby an emergency call received at a telephone exchange in a failure situation is directed to a subscriber line connected to the telephone exchange for emergency calls. The subscriber line may be con- nected e.g. to an exchange room in conjunction with the telephone exchange. According to the invention, the telephone network comprises a mobile station connected to the telephone exchange and used to transmit emergency calls. Further, according to the invention, the telephone exchange comprises an adapter connected to the mobile station to carry out the dialling for an emergency call in the mobile station and connect the emergency call to the mobile station. In addition, the system may comprise a directional antenna connected to the mobile station to improve its reception. In an embodiment of the invention, the system comprises means in the telephone exchange for monitoring the call setup request given by a subscriber and, based on this monitoring, call setup via the subscri- ber line connected for emergency calls is disabled if it is discovered that the connection is intended for a call other than an emergency call. In the following, the invention is described in detail by the aid of a few examples of its embodiments by referring to the attached drawing, which is a diagram representing a system according to the present invention. The system presented in the drawing comprises telephone exchanges 1 and la, which are connected to each other via an interconnecting line 2. Connected to telephone exchange 1 is a terminal device 3, which can be used to set up a call via the telephone exchange 1. Telephone exchange la is further connected to e.g. to another network 7. The other network may be any public telephone network. The telephone exchange may also be the access node of a wired or wireless local loop, in which it functions as a concentrator, concentrating the subscribers connected to it onto the link 2. In this case, the link 2 may be e.g. a dynamic V5.2 concentrator interface consisting of one or more (1 - 16) PCM (Pulse Code Modulation) lines. The telephone ex- change or access node 1 is also provided with means 6 for monitoring the number dialled by the subscriber in a failure situation, e.g. in the case of a fault in the interconnecting line 2 or telephone exchange la. Based on this monitoring, only a call addressed to an emergency number is accepted and directed to the subscriber line connected for emergency calls in telephone exchange 1. The system presented in the figure further comprises an adapter 5 connected to telephone exchange 1. Connected to the adapter 5 is a mobile station 4, which is used to set up an emergency call connection in the event of a failure in the system. Often the mobile communication network in which the mobile station 4 works is, in respect of the transmission paths be- tween the mobile communication exchanges and the base stations, independent of wired networks, and thus it functions even in the failure situations referred to above. Further, in weak mobile communication fields it is possible to use a directional antenna 6 physically located e.g. on the roof of the telephone exchange 1 (presented in the figure only as an example) . As summary, it can be further stated that the change required by the system of the invention in the network components currently used can be effected via relatively small technical measures. The telephone exchange already has a feature for directing emergency calls to a subscriber line connected for emergency calls, which may be located e.g. in an external box of the exchange. In addition, there are mobile stations 4 with a feature that allows computer-controlled dialling, which is effected by connecting the mobile sta- tion to a computer via a connector provided in it. Therefore, only an adapter 5 is needed between the mobile station 4 and the telephone exchange 1, and the adapter may be a computer which carries out e.g. the dialling of "112" in the event that a call is directed to the subscriber line connected for emergency calls. In addition, the adapter 5 performs the call connection after the mobile station 4 has carried out the dialling. The technical implementation of the adapter 5 is obvious to the person skilled in the art and is therefore not defined here in detail. The invention is not restricted to the examples of its embodiments described above, but instead many variations are possible within the framework of the inventive idea defined by the claims.

Claims: CLAIMS 1. Procedure for ensuring an emergency call in a telephone network comprising a number of telephone exchanges, the connections between which are imple- mented using interconnecting lines and to which are connected a number of terminal devices used to set up connections via the telephone network, and in which procedure, in a failure situation, an emergency call received at the telephone exchange is directed to a subscriber line connected for emergency calls, c h a r a c t e r i z e d in that a mobile station is connected to the subscriber line for emergency calls and the emergency call is transmitted further from the subscriber line via the mobile station. 2. Procedure as defined in claim 1, c h a r a c t e r i z e d in that the mobile station is connected to the subscriber line for emergency calls via an adapter. 3. Procedure as defined in claim 1 or 2, c h a r a c t e r i z e d in that the dialling for an emergency call is received at the telephone exchange; in the event of a failure in the telephone network, the dialling for the emergency call is connected to the adapter; and the dialling for the emergency call and the connection of the call to the mobile station are carried out by means of the adapter. . Procedure as defined in any one of the preceding claims 1 - 3, c h a r a c t e r i z e d in that a directional antenna is connected to the mobile station; and the directional antenna is used to improve reception in the mobile station. 5. Procedure as defined in any one of the preceding claims 1 - 4, c h a r a c t e r i z e d in that the mobile station works in the GSM network, NMT network, ARP network and/or equivalent. 6. Procedure as defined in any one of the preceding claims 1 - 5, c h a r a c t e r i z e d in that the call setup request given by the subscriber is monitored in the telephone exchange and, based on this monitoring, transmission of the call via the subscriber line connected for emergency calls is prevented if it is discovered that the call is intended for commu- nication other than emergency communication. 7. Procedure as defined in any one of the preceding claims 1 - 6, c h a r a c t e r i z e d in that the emergency call is an automatic alarm message, an alarm call or the like. 8. System for ensuring emergency communication in a telephone network comprising a number of telephone exchanges (1, la), to which is connected a subscriber line for emergency calls, the links (2) between which are implemented using interconnecting lines and to which are connected a number of terminal devices (3) used to set up connections via the telephone network, and which system comprises an arrangement whereby an emergency call received at a telephone exchange in a failure situation is directed to a subscriber line connected for emergency calls in the telephone exchange, c h a r a c t e r i z e d in that the telephone network comprises a mobile station (4) connected to the telephone exchange and used to transmit emergency calls; and that the telephone exchange comprises an adapter (5) connected to the subscriber line for emergency calls and to the mobile station to carry out the dialling for an emergency call in the mobile station and connect the emergency call to the mobile station. 9. System as defined in claim 8, c h a r a c t e r i z e d in that the system comprises a directional antenna (6) connected to the mobile station to improve its reception. 10. System as defined in claim 8 or 9, c h a r a c t e r i z e d in that the system comprises means (7) to permit the call setup request given by a subscriber to be monitored in the telephone exchange and, based on this monitoring, call setup via the subscriber line connected for emergency calls is prevented if it is discovered that the connection is in- tended for a call other than an emergency call.

Inventors: HAEGGMAN JUHA, KONTTINEN MARKO, HAEGGMAN, JUHA, KONTTINEN, MARKO
Applicants: HAEGGMAN JUHA, KONTTINEN MARKO, NOKIA TELECOMMUNICATIONS OY, HAEGGMAN, JUHA, KONTTINEN, MARKO
Application year: 1997
Main classification: H04M11
IPC codes: H04M3, H04M7, H04M11