DE19821567C2 - Call forwarding - Google Patents

Description

The invention relates to a method for forwarding a call within a Telecommunications network consisting of several interconnected subnets according to the preamble of claims 1, 2 and 3.

The subnets should either be simple cordless telephones (a radio cell with several participants) or with telecommunication systems (telecommunications systems) trade multiple radio cells for cordless phones. The best are for this Plants according to the DECT standard currently prevailing on the market.

DE 44 27 072 C1 describes a method for call forwarding within a Known telecommunications network, which consists of connected sub-networks and in which If the subscriber in the selected network does not reach the other subnets after Participants are searched or an instruction is sought that another Availability z. B. Answering machine is possible. The subnets are digital Connection network (dial-up network) connected to each other and the connection is made via a Bridgehead, which acts as an exchange and makes certain adjustments. Mobile networks based on the GSM standard or other forms are possible subnets provided by large cell radio systems; forwarding is only possible Large cell radio systems based on the GSM standard.

Methods for call forwarding are known from DE 195 38 882 A1, in which Calls for a cordless phone are forwarded to specified phone numbers. The proposed technical solution works according to the "Call Deflection" - or "Call Forwarding with partial rerouting "method.

From DE 196 17 441 C1 it is known to use cellular and cordless telephone networks connect with each other. A dual-mode telephone is required, and that Home register of the mobile network is used to determine the location of the dual mode  Store phone; At the same time, the data in the Home register of the mobile network.

DE 43 44 702 A1 describes a method for call forwarding in one Mobile network known if the called subscriber cannot be reached in the mobile network is. This is first done on a DECT connection within a fixed network and, if this unsuccessful, switched to an answering machine. The specified procedure requires a dual-mode handheld device.

From DE 39 11 915 A1 a device is known which has two exchange lines connected is. The line that is not seized by the caller transfers a call to a forwarded phone number stored in the device. Here both get the caller and the subscriber dialed under the new telephone number have one Message about the forwarding process.

A dual-mode telephone is known from DE 43 44 702 A1, but if it cannot be reached the phone via the mobile phone number to the fixed network number of a DECT radio network is switched. If the called party is also not available at this number, is on forwarded a third landline number. The different phone numbers are in the exchanges stored.

Starting from a method as specified in DE 44 27 072 C1, the The object of the invention is to provide a simple, inexpensive and fast method for Provide call forwarding.

This is with the features of both claim 1 and claims 2 and 3 solved.

All processes have in common that they special features of the digital Use telecommunications networks so that they are fast and inexpensive; so fees only arise when a connection is established.

Advantageous refinements are specified in the dependent claims.  

Advantageous configurations are in the dependent An sayings.

The invention is exemplified in the description posed.

Here show:

Fig. 1 shows a schematic representation of a Telecommunicati onsnetzes consisting mennetzen of a public and three Fir,

Fig. 2 Block flow diagram of the first OF INVENTION to the invention process,

Fig. 3 block diagram of the sequence of the second inventive method and

Fig. 4 block diagram of the sequence of the third inven tion inventive method.

Fig. 1 shows schematically a designated 1 public digital telecommunications network z. B. ISDN network of German Telekom, to which various independent subnetworks (company networks) FA, FB, FC are connected. These can be in different areas, but also in the same location but in different locations. In the network configuration shown in FIG. 1, it is assumed that the company networks FA, FB, FC have DECT radio networks; therefore base stations BA, BB, BC and mobile parts MA1, MA2, MB1, MC1 are specified. The company networks FA, FB, FC have central systems on so-called telecommunications systems, via which they are connected to the public digital telecommunications network and which offer the possibility that special features of digital telecommunications networks such as subaddressing or subscriber-to-subscriber signaling are evaluated can be. In the various PBXs, a storage area is stored in which other PBXs (company networks) FA; FB, FC a handset MA1, MA2,. , , should be searched.

Now a participant goes out with his handset MA1, MA2,. , , in another company network e.g. B. FB, the if his network of origin is not FA, he can register there the. The first time you register, registering a new / foreign handset in one Understood subnet. Registration usually happens always manually by the user to avoid abuse prevent. When registering, the handset will receive an in assigned to the internal phone number (extension number). This Extension number can also be an extension number his. With an ISDN network, point-to-multipoint Connections (abbreviated: PMP) a multiple phone number access order to connect the handset directly from the outside choose. On the other hand, the procedure is checked in here understood that when entering a registered handset in the area of the radio cell of a subnet. To the handset can be reached after checking in. Is a handset not registered or logged in, so it is the Zentralsy stem of the subnetwork not known. But since the handset by identifying its air interface is clearly defined, the central system of the subnet zes also one that can be reached in its radio range, but not determine the registered or registered handset; d. H. the handset is known to the subnet, but it was not accepted.

In FIG. 2, a first inventive search and handoff process there is shown in the form of a Flußdia program. If a subscriber is called in the company network FA, the central system of this company network FA checks whether the subscriber can be reached in one of the radio cells. If the check is successful, the caller is connected. The central system has two options. If an extension or multiple number is assigned to the handset, the handset can be addressed directly. However, if none of the above numbers are assigned to the handset, the handset is dialed using the transmitted identification code. This identification identifier can, for example, be present as a subaddress in the setup frame of the pending call. If the check leads to a negative result, the central system in the company network FA begins to dial the various other company networks FB, FC with their telephone numbers and transmits the identification of the handset through special service features of the digital connection network. The identifi cation ID can either be taken from a list in the central system - this is an assignment list, through which extension or multiple numbers and identification codes are assigned to each other - or from the setup frame of the incoming call. When the identification code is removed from the setup frame of the pending call, a chaining of searching PBXs is possible. In Fig. 2, the company network FC should first be selected. After successful transmission of both the subscriber number in the originating network FA and the identification identifier, the connection to the subnet FC is broken off. In the ISDN network there is a transmission of the caller's call numbers (source information) under the so-called "calling address" and the identification code via z. B. subaddressing. After receiving these two data, a dial tone is sent, on the basis of which the originating network FA terminates the connection. Due to the rapid initiation of the search connection (reception of the "Discon nect" signal), the handset MA1 would not be called at this point in time even if it were present. If necessary, a delay timer must be provided here. The same process is repeated with respect to the company network FB. Through the central systems of the company networks FC, FB he then checks the accessibility of the mobile part MA1. If the handset MA1 cannot be reached, no further action is taken. If the handset MA1 is reachable in a subnetwork, here the subnetwork FB, then this subnetwork FB establishes a reply connection to the original network FA. This is done in that the original network FA with the subscriber number is selected by transferring the subscriber number in the subnet FB. The central system of the originating network FA knows it (in the time window of the waiting call) based on the dialed subscriber number the subscriber and puts the waiting caller through with the answer connection now existing to the subscriber. The answer connection can also be identified by retransmitting the identification identifier as a subaddress.

Another possibility ( FIG. 3) is to send only a positive message to the originating network FA and thereby causing the originating network FA to set up a connection to the location found. This can happen again in such a way that after transmission of the two subscriber numbers - ie the number in the primary network FA as well as the number under which the handset can now be reached in the other subnet FB - and the identification code, the connection between the subnets is terminated. The connection is then re-established by evaluating the transmitted subscriber numbers and the identification identifier. The location is identified in the central system of the company network FA and when a call is made again, this location is first started with the search.

Another variant, as described in FIG. 4, consists in maintaining the connection until either positive or negative feedback is given by the selected subnetwork FB, FC. Depending on this, the call is put through or another subnet is selected.

Company-specific fixed connections (third-party networks) can of course be used for this search. Companies are often connected via an in-house data network (intranet). For example, the local area networks (LAN) are connected to one another via leased lines (WAN). A connection via the Internet is also conceivable. If the PBXs according to the invention are connected to the network at the respective locations (HUB), direct contact of the systems with one another (IP addresses) is possible at low cost. A PABX system that is looking for a mobile device now compiles a "search data record". This consists at least of an identification code of the handset to be searched and a "search reference value" in order to classify incoming answers. This "search data record" is transmitted to the PBXs where the handset is to be searched (FA, FB, FC) (selection by IP address). These PABX systems always send a "response data record" or only if the search is successful. This contains at least the received "search reference value" and a phone number under which the handset can now be reached. In the original PBX, the "response data record" is classified based on the search reference value. The further process (selection, connecting the part stretch) then takes place as shown in Fig. 3. There is also the option of assigning an extension or multiple call number to an accessible handset for a limited time. The handset you are looking for can thus be temporarily selected directly (without an identification code as a subaddress). This option is necessary when the number is announced under which the handset was found. This assignment can then be canceled either after the time has elapsed or after the end of a call that has come about.

Claims (9)

1. Method for forwarding a call within a telecommunication network consisting of several interconnected sub-networks,
wherein if the subscriber is not reached in the selected first subnetwork (FA), connections to the other subnetworks (FB, FC) are established and signaling data are transmitted and
the telephone call is put through in the other subnets (FB, FC) when the subscriber is reached,
characterized by
that the sub-networks (FA, FB, FC) are connected to one another via a digital dial-up network ( 1 ) and are radio networks for cordless telephones or contain radio networks for cordless telephones,
that the connections to the other subnetworks (FB, FC) are established one after the other and with the help of special features of the digital connection network the identification code of the air interface of the handset (MA1) and the source number are transmitted,
that the connection to the subnetworks (FB, FC) is interrupted by the dialing subnetwork (FA) when the identification ID of the air interface of the handset (MA1) and the source number have been successfully transmitted, and
that the subnetworks (FB, FC) check the accessibility of the handset (MA1) based on the transmitted identification code and, if the check is successful, establish a connection to the first selected subnetwork (FA). 2. Modified method according to claim 1, characterized in that that if the check is successful, positive feedback on the first selected Subnet (FA) is sent, which then connects to this subnet (FB, FC) builds. 3. Modified method according to claim 1,
that the connection from the dialing subnet (FA) to the selected subnet (FB, FC) is maintained until the check is complete and
that if the check is unsuccessful, the connection is broken down and set up to a further subnet (FC) in order to check the accessibility. 4. The method according to claim 1 or 2, characterized in
that the caller is informed of the subscriber number under which the handset (MA1, MA2,...) can be reached and
that the connection to the caller is cleared after the announcement. 5. The method according to claim 1, 2 or 4, characterized in that there is a second connection network through which the individual search queries to the subnets (FB, FC) and the response messages to the first subnet (FA) be transmitted.   6. The method according to any one of the preceding claims, characterized in that the identifier of the subaddress in the setup frame of the pending From the call. 7. The method according to any one of the preceding claims 1-5, characterized in that the identifier identifies the information element of the subscriber Subscriber signaling is taken from the setup frame of the pending call. 8. The method according to any one of the preceding claims, characterized in that about the identification code based on one contained in the first subnetwork (FA) List the extension or assigned to the handset (MA1, MA2,...) Multiple phone number is determined. 9. The method according to any one of the preceding claims, characterized in that
that the subnet (FB, FC), in which the handset (MA1, MA2,...) can be reached, assigns the extension or multiple number to the handset (MA1, MA2,...) after an automatic registration process,
that the extension or multiple number is transmitted to the first subnet (FA) when the second subnet (FB, FC) is selected and
that after termination of the user connection or a period of time determined by a timer, the assignment of the extension or multiple number to the handset (MA1, MA2,...) is canceled.