CN1227695A

CN1227695A - Device and method in telecommunication equipment

Info

Publication number: CN1227695A
Application number: CN 97197110
Authority: CN
Inventors: T·贝里格伦; J·奈曼
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 1996-08-06
Filing date: 1997-08-01
Publication date: 1999-09-01
Also published as: SE9602932L; AU3791097A; SE9602932D0; WO1998006224A1; NO990526D0; NO990526L; EP0976257A1; AU722120B2; SE517557C2

Abstract

The present invention relates to a device for connection to a public telecommunication network (IVN) and comprises at least two exchange units (PINX, PINX2, CENTREX AXE) to which subscriber terminals can be connected, such as an exchange unit and a method for interconnecting two such exchange units. Each exchange unit (PINX, PINX2, CENTREX AXE) comprises a control means, which is arranged to be able to detect a request, coming from a subscriber terminal connected to a first exchange unit (PINX1), for the connection to a second subscriber terminal connected to a second exchange terminal (PINX2, CENTREX AXE) and to set up, through signaling and in dependence of said detection, a special signaling channel through the public telecommunication network between the own exchange unit and the other exchange unit if no such signaling channel already exists and to set up a speech channel between the two exchange units.

Description

Apparatus and method in the telecommunication apparatus

Technical field

The present invention relates to the apparatus and method in the telecommunication apparatus, and be specifically related to by public telecommunication network connect two crosspoints that are mutually related method, comprise the device of at least two such crosspoints and such crosspoint.

The state of prior art

In the field of telecommunications that relates to private exchange unit (as associating switch (corporate exchange)), exist some problems, and this occurs in several different crosspoints and is connected to public telecommunication network and wishes that these crosspoints resemble for the user under the situation of working the single switch, and promptly the extraneous information that the user can visit in crosspoint can be sent under the situation of other crosspoint in the system by public telecommunication network.As everyone knows, this can realize by the leased line between two such crosspoints.Yet, because this circuit often is no, so this is a kind of expensive solution.

US-A-5212691 has disclosed two kinds of PBX (private branch exchange) by the interconnection of ISDN net.Between these PBX, many empty direct trunks can connect by the ISDN net.In these circuits one has constituted the signaling channel between two PBX, and other circuit has then constituted the voice channel circuit.These virtual circuits are set up according to calendar data, as in which day and one day when.

US-A-5422943 has disclosed and has comprised several networks of being netted the PBX of interconnection by ISDN.Voice-and-data can be in transmission over networks.

EP-A2-584537 has disclosed use ISDN net subscriber exchange has been interconnected.The signaling information that transmits between the switch connects by packet switching to be finished, and speech business then connects based on the basic rate type.

EP-A2-641140 has disclosed virtual joint network, and wherein specific call signaling information is to transmit with the form of data-message between subscriber exchange, and it transmits in identical channel with call.

The description of invention

The problem that the present invention handles is how to interconnect at least two crosspoints in the joint network so that transmit the specific information of joint network by public telecommunication network, and need not use leased line between the crosspoint, and need not use the coding of the joint network specific information on any voice channel yet.

Another problem that the present invention handles is how in the establishment of connection time and number between the control crosspoint, and further at least two crosspoints of interconnection are to transmit the joint network specific information.

Therefore, an object of the present invention is need not use leased line so that transmit the joint network specific information by two crosspoints in the public telecommunication network interconnection joint network.

These problems are to solve by such fact, promptly in the time will between two crosspoints, setting up calling, if the previous ongoing call setup Dedicated Signaling Channel of Shang Weiwei, just set up such signaling channel by public network, the joint network specific information just can transmit on signaling channel like this.

Therefore these problems can solve by the method that may further comprise the steps:

Detect the foundation request to second user that is connected to second crosspoint at first crosspoint by first user who is connected to first crosspoint, if there is no such signaling channel is then set up a definite signaling channel by network for these two crosspoints according to described detection, and between two crosspoints, set up a voice channel, so that set up the calling between first and second users.

These problems still solve by such crosspoint, user terminal can be connected to this crosspoint, and this crosspoint comprises a control device, its detects the request of setting up to second user terminal that is connected to second crosspoint that is proposed by first user terminal that is connected to crosspoint, if and still do not have such signaling channel, then according to described detection, rely on signaling to set up its crosspoint and the Dedicated Signaling Channel between second crosspoint, and set up voice channel between first and second subscriber channels to set up the calling between them by public telecommunication network.

These problems also are by a kind of device solves that comprises at least two such crosspoints.

Advantage of the present invention is two crosspoints that only just interconnect when message transmission is arranged, and does not have connection At All Other Times between two switches.Another advantage of the present invention is, is based upon between the crosspoint by public network and connects except that voice connect one of only many use.This just provides a low-down system of cost, because the connection by public network only just sets up when the actual use of network, and does not need to use expensive leased line or expensive fixedly connected each other at crosspoint when very far away.In addition, the resource of crosspoint has obtained better utilization, owing to do not set up unnecessary fixedly connectedly, makes crosspoint more flexible.

Also the invention will be further described with reference to the accompanying drawings will to use preferred embodiment now.

The description of accompanying drawing

Fig. 1 shows the theory diagram according to crosspoint of the present invention,

Fig. 2 shows the theory diagram of the small-sized joint network that is connected to public telecommunication network,

Fig. 3 shows the flow chart of the method according to this invention, and

Fig. 4 schematically shows how produce signaling according to the present invention.

Preferred embodiment

Fig. 1 shows simplification crosspoint according to a preferred embodiment of the invention.Preferred crosspoint PINX1 is associating switch, for example the MD110 type of Ericsson.This associating switch comprises the exchcange core 10 that has connected control device 12.Control device 12 is used to control the calling switching by switch.A plurality of

user terminals

14 and 10 circuit T1-T10 that go out also are connected to exchcange core 10.Two so-called Signal Terminal ST are connected to exchcange core 10.A DID-memory 16 (DID represents " direct dialing (Direct-In-Dialing) " here) also is connected to control device 12.Comprise special telephone number in the DID-memory 16, they are used for the calling between of the joint network initiating and set up unit PINX1 and comprise this associating switch or some other crosspoints.Known as those skilled in the art institute, user 14 is connected to the circuit T1-T10 that goes out by switch 10 under the control of control device 12, be established to another user who is connected to another node (as another associating switch) or the calling that is directly connected to another user of public telephone network.Signal Terminal ST also can be connected to the circuit of going out under the control of control device 12.

Every line shown in the figure all is two-way with being connected, so business can be passed through on both direction.

The existence of Signal Terminal ST makes crosspoint to communicate by letter with another crosspoint according to predetermined agreement, therefore can send the joint network specific information.Certainly, this requires second crosspoint also to comprise a Signal Terminal.The joint network specific information means whether the line is busy for the called phone number about whom is caller and his telephone number such as, the whether diverting call of called phone number, if, where transfer to, whether the callee waits information in session.All these information of transmission are important in joint network.Associating switch shown in the figure has included only two Signal Terminal ST, and therefore this associating switch can only be connected to two other crosspoints simultaneously.The associating switch can include only one or comprise considerable Signal Terminal very naturally.The number of the Signal Terminal in the crosspoint depends on that a crosspoint wishes to transmit simultaneously the number of other crosspoint of joint network specific information.Equally, the number of users that is connected certainly is different with the circuit number of going out.Crosspoint according to the present invention is not limited only to the associating switch, also comprises for example so-called centralized Private Branch Exchange PBX (centrex) unit simultaneously.A centralized Private Branch Exchange PBX unit is the part of a switch in the public network, and as the part of AXE-switch, and it is used as an associating switch.Control device and Signal Terminal always are positioned among the centralized Private Branch Exchange PBX part of public exchange.

Fig. 2 shows that one has two associating switch PINX1 and PINX2, and the simplification joint network of a centralized Private Branch Exchange PBX unit CENTREX AXE.Omitted control device among the figure, DID-memory and exchcange core are to simplify.Yet associating switch PINX1 and PINX2 come down to the same type with Fig. 1 associated description.

Two associating switches are connected to public network IVN by the the the first, the second, the three, the four, the the five, the six, the seven, the eight and the 9th circuit T1-T9 and T11-T19 respectively, and the public network IVN in this preferred embodiment is ISDN net (integrated services digital network).Yet this is equivalent to PSTN net (public switched telephone network).The first associating switch PINX1 also has one article of the tenth circuit T10 that goes out to link to each other with public network IVN.Centralized Private Branch Exchange PBX unit also is connected to public network by the first, the second, the third and fourth circuit T20-T23.All circuits among the figure also are two-way.The second, the third and fourth circuit T2-T4 that leaves the first associating switch PINX1 is connected to corresponding the second, the third and fourth circuit T12 that leaves the second associating switch PINX2, T13, and T14, that is, they are by public network IVN interconnection.Leave the 5th circuit T5 of their associating switches separately and the signaling that T15 is used for public telephone network, that is, they are used as the D-channel with respect to the ISDN net.If the associating switch is connected to a common PSTN net, obviously these circuits will be used for general service and the signaling by general B-channel connection.Leave the the seven, the eight and the 9th circuit T7 of the first associating switch PINX1, T8 and T10 and leave the first, the second of centralized Private Branch Exchange PBX unit CENTREX AXE and link to each other with tertiary circuit (T20-T22).Centralized Private Branch Exchange PBX unit CENTREX AXE also is used for isdn signaling with its 4th circuit T23, and this circuit obviously also is used for general service when public network is the PSTN net.

The first Signal Terminal ST that the first Signal Terminal ST and second among the first associating switch PNIX1 unites among the switch PINX2 links to each other with T14 and public network IVN by the 4th circuit T4 that leave the first and second associating switch PINX1 and PINX2 separately, and the signal end of secondary signal terminal ST among the first associating switch PINX1 and centralized Private Branch Exchange PBX unit CENTREX AXE links to each other with the tertiary circuit T22 and the public network IVN that leave centralized Private Branch Exchange PBX unit CENTREX AXE by the 9th circuit T9 that leaves the first associating switch PINX1.All circuits that leave crosspoint play interconnect function and use one to be called as No.ETS300172 " special comprehensive service network (PISN); Interoffice exchange of signaling agreement; The circuit-mode basic service " agreement communicate by letter with public network IVN by business interface (C), and each Signal Terminal uses one to be called as No.ETS300402 " Integrated Service Digital Network digital subscriber signaling system number one (DSSI) respectively; Data link layer " agreement by signaling interface (Q) each other communication.These interfaces are shown in dotted line in the drawings, under the situation of business interface (C), be connected public network and crosspoint PINX1 separately with all, the circuit of PINX2 and CENTREX AXE intersects, under the situation of signaling interface (Q), intersect with the inner connecting line that is connected each Signal Terminal ST and public network of crosspoint.No matter the circuit of the signaling of any kind that is useful on is to public network or to other crosspoint, all represents with thick line.Crosspoint is not to be connected with each other forever according to the method shown in the figure, but only when needed, promptly will set up when calling out, and connects according to the method shown in the figure.When not having professional the generation between two crosspoints, the signaling channel between the Signal Terminal or any voice channel do not connect.How the process of setting up takes place and will describe with reference to figure 3 and 4 below.

As shown in Figure 2, two Signal Terminals are crossed two interfaces (business interface (C) and signaling interface (Q)) and are communicated with one another, and the user terminal (not shown) that is connected to crosspoint is only crossed business interface (C) and is communicated with one another, that is, the agreement that is used for signaling channel than the agreement that is used for voice channel at higher level.

Shown in Fig. 2, two callings are the user who is connected to the first associating switch PINX1 and be connected between the user of the second associating switch PINX2 and carry out.For cause clearly, omitted the user terminal at ongoing calling two ends among the figure.First calls out B1 is undertaken by the second circuit T2 and the T12 that leaves the first and second associating switches, and the second calling B2 is undertaken by tertiary circuit T3 and the T13 that leave the first and second associating switches.These two the joint network specific informations of calling out B1 and B2 are by signaling channel (D1-2) transmission, and this signaling channel is to set up by the 4th circuit T4 that leaves the first and second associating switches and T14.

Use the same method, call out B1 and B2 for two between the first associating switch PINX1 and the centralized Private Branch Exchange PBX unit CENTREX AXE, unite the 7th circuit T7 and the first circuit T20 that leaves centralized Private Branch Exchange PBX unit of switch by leaving first, and undertaken by the 8th circuit T8 that leaves the first associating switch and the second circuit T21 that leaves centralized Private Branch Exchange PBX unit.Also set up the joint network specific information employed signaling channel (D1-2) relevant by the 9th circuit T9 that leaves the first associating switch and the tertiary circuit T22 that leaves centralized Private Branch Exchange PBX unit with these callings.

Signaling channel (D1-2) is set up by the D/B signaling, that is, public network IVN regards them as usual speech channel, the B-channel, and crosspoint is regarded them as the D-channel.Can certainly be only by the joint network specific information of such signaling channel transmission more than two callings.

Fig. 3 provides the flow chart of setting up the method for calling according to the present invention, and how Fig. 4 sets up signaling channel and voice channel with the arrow signal between two private exchange unit.8 continuous vertical lines are arranged among Fig. 4, from left to right represent TC, DRC, Q, C, C, Q, DRC, TC.Space representation IVN in the middle of the line of expression C.Leftmost TC (terminal connection) expression is connected to the user of the first associating switch, the control device of DRC (Dynamic Route Control device) in representing the first associating switch thereafter, Q represents the signaling interface in the first associating switch, C is the business interface between the first associating switch and the public network, and IVN is a public network.After this, C represents the business interface between second associating switch and the public network, and Q is the signaling interface in the second associating switch, and DRC is the control device in the second associating switch and last TC is the user who is connected to the second associating switch.

How Fig. 4 exhibition information is transmitted between two associating switches.How describe signaling channel and voice channel referring now to Fig. 3 and 4 sets up between two associating switches.The shown figure and the method for description only are the situations of two associating switches, but obviously this method also can be used for a situation of uniting switch and a centralized Private Branch Exchange PBX unit or two centralized Private Branch Exchange PBX unit.

With reference to figure 3 and 4, the method according to this invention is worked according to following mode.When first user (representing with TC among Fig. 4) who is connected to the first associating switch wants to connect second user when (also representing with TC among Fig. 4), but these two users belong to same joint network different associating switch, and first user dials the telephone number that is second user's correspondence.This by shown in the arrow between TC and the DRC line, is designated as " outg.call (going out to call out) " in Fig. 4, it represents the control device in first customer call, the first associating switch.Control device in the first associating switch detects this calling, method step 20, and execution is commonly referred to B-user to the analysis of second Subscriber Number.After if this is analyzed, control device finds that the B-number does not belong to the user in this joint network, method step 22, and it will be made great efforts according to setting up this calling by the common telephone call of public network, method step 24.Yet, if finding this number, control device belongs to the user who is connected to another the associating switch in the identical joint network, method step 22 is determined this second associating switch with regard to the number that uses first user to be dialled, and is carried out a new analysis.In this new analysis, whether the control device investigation has set up signaling channel, method step 26 between two associating switches.If set up a signaling channel, control device just selects special voice to connect or the DID-number is used as the calling to the second associating switch by public network IVN.After this between two associating switches, set up a voice channel for voice, and on the signaling channel of having set up, the joint network specific information is sent to second and unites switch, method step 28.

But, if do not set up signaling channel, method step 26, control device is just selected a special signaling channel request number and a signaling channel response number (these numbers are to be stored in advance in the DID-memory) from the DID-memory, and use other associating switch of these number calls, method step 30.This is to finish by such method: send a control device setup requests (by setupBcha (set upB-channel sets up the B-channel) expression) from control device to the C-reference point, and unite the signal (this in Fig. 4 by seizure (taking) signal indication) of switch by public network IVN to other.This seizure (taking) signal (according to the agreement that public network uses, it is a known call signal) comprises signaling channel request number and signaling channel response number.Yet,, only use a signaling channel request number if public network is the PSTN net.These two numbers are sent to second control device of uniting the switch from public network, are represented by estdrind (establish dynamic routeindividual sets up independent dynamic routing).Second control device is carried out the inspection of signaling channel response number, if this number is correct, just the signaling terminal with it is connected to signaling interface and uses the signaling channel response number answering call that is obtained, method step 32.Signal Terminal in the second associating switch is connected Fig. 4 the right to be represented with the arrow of two different directions between Q and the DRC line, represents with estdrindack (establish dynamic route individual acknowledged sets up independently dynamic routing and confirms) with the call answering that the signaling channel response number is made.Subsequently, this B-channel that is used as by the signaling channel of public network connects with " connected (connecting) " expression, this also is a known signal for the agreement of using according to public network, and the control device of first associating in the switch obtain a Bchacon (B-channel connected B-channel connects) signal, and expression B-channel is set up.After this, first control device is connected to signaling interface with its Signal Terminal, and the arrow of two different directions is represented between Fig. 4 left side is with Q and DRC line.After this, two Signal Terminals connect each other under the control of first Signal Terminal, and this is in the drawings shown in estL2 (establish L2 the sets up L2) signal that first control device sends to signaling interface.

After this, between two Signal Terminals between two signaling interfaces, set up stable connection, shown in two-way dotted line Layer2 (2 layers) among the figure.This connection is to use the HDLC agreement to shake hands between two Signal Terminals and sets up.Shake hands by L2est (L2established L2 sets up) signal respectively alert signal terminal signaling channel set up and finished.If public network is the network of a PSTN type and does not transmit the signaling channel response number during signaling, to on the signaling channel of being set up, carry out the identification of two signaling channels subsequently, that is, with carry out to check determine whether the second associating switch be exactly the first associating switch to connect that.Afterwards, signaling channel has been set up and the joint network specific information relevant with the calling that will set up transmits method step 33 on signaling channel.

After signaling channel is set up between two associating switches in this way, select voice to connect or a DID-number, and use this DID-number call second switch to set up voice channel, method step 34.This is performed such: the control device from the first associating switch sends an estdrreq (establish dynamic routerequest sets up the dynamic routing request) signal to public network IVN, to call out the second associating switch, this uses the seizure signal to carry out by public network.This signal also comprises the DID-number and replys number.This is called out by the second associating switch and receives as estdrind (establish dynamic route individual sets up independent dynamic routing) signal.The second associating switch inspection is replied number and is replied number according to the inspection use and replied by estdrindack (establish dynamic route individual acknowledged sets up independently dynamic routing and confirms) signal, and this sends as " connected connects " signal by public network and is received as estdrreqack (establish dynamic route request acknowledged sets up dynamic routing request affirmation) by the first associating switch.By this, set up the B-channel, and when transmitting joint network specific information (as A-and B-number) by signaling channel, calling can continue at this voice channel.

If public network is a PSTN net, will before setting up voice channel, be undertaken by signaling channel to the inspection of voice channel call number.

Signaling channel will keep during the calling of carrying out between two associating switches always, and be used to transmit the joint network specific information of the all-calls that is carried out between these two the associating switches.When last call clearing, signaling channel is also taken out stitches.It is known that channel is taken out stitches to those skilled in the art, does not therefore do more description here.

Can obtain a lot of benefits by above-described the present invention.At first, when there not being joint network specific information when transmission between two crosspoints, without any need for the circuit of renting, this has just been avoided using expensive leased line or other fixedly connected between them.The second, the use of crosspoint is more efficient, that is, the required capacity of the connection that keeps such can not be used for other purposes when having the transmission of joint network specific information between two crosspoints.

A large amount of different embodiment of the present invention are possible.The inspection request number of being mentioned needn't be carried out and also can partly carry out.In addition, if between the user who is connected to the first associating switch and be connected between second user of the second associating switch and set up call out, and be first customer call, second user, can set up the actual speech channel from second user according to different embodiment, make and see as second customer call, first user from public network.This will take place in this case, when first control device sees that signaling channel has been set up, sends the request of setting up voice channel from the first associating switch to the second associating switch by signaling channel, and the second associating switch is set up voice channel then.The different telephone expenses of country variant (for example according to) was very interesting when this calling of initiating at the second associating switch was more cheap than the calling of the first associating switch initiation.

Also can be chosen in the second associating switch and check signaling channel response number and DID-number.Be used for asking and number that response request is set up voice channel is selected with a kind of known method at the first associating switch according to arbitrary local numbering plan usually, still also can use A-and B-number, that is, directly belong to two users' number.

A further embodiment of the present invention can use compress speech.The associating switch comprises the compress speech unit, and it preferably also comprises Signal Terminal.The compress speech unit comprises according to the compression algorithm compressed voice, so that voice channel can be filled the more fraction that voice connect between two associating switches (normally 1/4th).The Signal Terminal that receives the channel of compression is expanded the voice of (in its compress speech unit) compression to obtain the voice of conventional size.A large amount of connections of uniting in this way between the switch can further reduce, even can guarantee also can be used for voice channel as connection or channel that signaling channel is set up.This connection generally includes three voice channels and signaling channel, and more the connection only uses under the occupied situation of whole signaling channel connection space.

Control unit in the crosspoint is also equipped error-detecting facility usually, in order to monitor the mistake on the channel of setting up by public network and to reconnect because the channel that wrong (for example, because the public network fault) causes is taken out stitches.

In description, mentioned voice channel and be for the call setup between two users.Such voice channel can certainly be set up for transmitting data or video (signal).

The present invention is specially adapted to the crosspoint situation of wide apart each other in the joint network.They in addition can be positioned at different countries.

The present invention also can be in conjunction with set up signaling and voice channel according to calendar data.

Describe above the present invention is not restricted to naturally and in the accompanying drawings shown in embodiment, but can in the scope of appended claims, revise.

Claims

1. connect two crosspoint (PINX1 that are mutually related by public telecommunication network (IVN), PINX2, CENTREX AXE) method, be included in and detect the foundation request to second user that is connected to second crosspoint (PINX2) (20) in first crosspoint (PINX1) by first user (14) who is connected to first crosspoint, it is characterized in that, if there is no such signaling channel (26,33) then set up a Dedicated Signaling Channel (D1-2) by network for these two crosspoints according to described detection, and at two crosspoints (28,34) between be between first and second users the call setup voice channel (B1, B2).

2. according to the method for claim 1, it is characterized in that transmitting the joint network specific information of calling out between first and second users by signaling channel (D1-2), even (B1 also can take place when B2) taking out stitches (28) voice channel that described transmission is former is set up when setting up signaling channel first.

3. according to the method for claim 1 or 2, it is characterized in that if be connected two crosspoint (PINX1, PINX2) between and use signaling channel (D1-2) to transmit all voice channels of joint network specific information (B1 B2) takes out stitches, this signaling channel (D1-2) of just taking out stitches.

4. according to the method for any aforementioned claim, the foundation that it is characterized in that signaling channel is included in special signaling channel request number of selection in first crosspoint (PINX1), and use this special signaling channel request number to send request to second crosspoint (PINX2), so that set up signaling channel (30) from first crosspoint.

5. according to the method for claim 4, the foundation that it is characterized in that signaling channel (D1-2) also comprises, in first crosspoint (PINX1), select the signaling channel response number, this signaling channel response number sends in the request that sends with signaling channel request number, depend on the inspection of signaling channel response number simultaneously, use signaling channel response number is replied the request from second crosspoint (PINX2), to set up signaling channel (32).

6. according to the method for claim 4, the foundation that it is characterized in that signaling channel is included in to send uses the signaling channel inspection signaling channel of shaking hands before the joint network specific information, and at the signaling channel of taking out stitches when not having correct execution of shaking hands.

7. according to the method for any aforementioned claim, the foundation that it is characterized in that voice channel is included in special voice connection number of selection in first crosspoint, and use this specific human voices to connect number (28,34) by public telecommunication network and set up voice channel to second crosspoint from first crosspoint.

8. according to the method for one of any claim 1-6, the foundation that it is characterized in that voice channel is included in and sends voice channel from first crosspoint to second crosspoint on the signaling channel and set up request, in second crosspoint, select special voice to connect number, and use this specific human voices to connect number and set up voice channel from second crosspoint to first crosspoint by public telecommunication network.

9. according to the method for any aforementioned claim, it is characterized in that compressing each voice channel and by public telecommunication network one and set up several voice channels with identical being connected.

10. according to the method for claim 9, it is characterized in that using the voice channel of setting up by the connection of public telecommunication network foundation to be used for signaling channel by such method, promptly the space corresponding to the voice channel that compresses is used for the subscriber signaling channel, and the voice channel that other space is used to compress.

11. connect public telecommunication network (IVN) and can connect the crosspoint (PINX1) of user terminal, it is characterized in that, control device (12) is used to detect foundation that first user terminal (14) that is connected to this crosspoint the initiates request to second user terminal that is connected to second crosspoint, and if there is no such signaling channel, then depend on described detection, use signaling by public telecommunication network (IVN) oneself crosspoint and other crosspoint between set up a special signaling channel (D1-2), and (B1 is B2) to set up the calling between them to set up a voice channel between first and second user terminals.

12. crosspoint according to claim 11, it is characterized in that an exchcange core (10) and a large amount of circuits of going out (T1-T10), wherein said control device (12) is connected to this exchcange core, and the tie point of each user terminal (14) can switch on the circuit of going out by exchcange core.

13., it is characterized in that a DID-memory (16) that is connected to control device (12) according to the crosspoint of claim 12.

14. crosspoint according to one of claim 12 or 13, it is characterized in that crosspoint can be connected to the Signal Terminal of each additional crosspoint (ST), each Signal Terminal all is connected to exchcange core (10), so it can be connected to any circuit of going out.

15. crosspoint according to one of any claim 11-14, it is characterized in that if set up signaling channel (D1-2) by the network between this crosspoint and second crosspoint, control device just is used to it to transmit the joint network specific information that the user between these two crosspoints afterwards connects, even at first Qing Qiu the voice channel of being set up has been taken out stitches or has been about to and takes out stitches.

16., it is characterized in that control device (12) is used for this signaling channel of taking out stitches when all voice channels that signaling channel of the use of being set up transmits the joint network specific information have been taken out stitches between two crosspoints according to the crosspoint of claim 11 or 12.

17. be used to connect public telecommunication network (IVN) and comprise at least two crosspoint (PINX1 that can connect user terminal (14), PINX2, CENTREX AXE) device, it is characterized in that, each crosspoint (PINX1, PINX2, CENTREX AXE) comprises a control device (12) or have the right to visit a control device, this control device can detect from first user terminal (14) that is connected to relevant crosspoint (PINX1), so that to being connected to the second crosspoint (PINX2, the foundation request of second user terminal CENTREX AXE), and if there is no such signaling channel, then depend on described detection, use signaling by public telecommunication network oneself crosspoint and other crosspoint between set up a special signaling channel, and between first and second user terminals, set up a voice channel to set up the calling between them.

18. the method by two crosspoints that are mutually related of public telecommunication network connection comprises

At first crosspoint, detect by the foundation request of first user terminal that is connected to first crosspoint to second user terminal that is connected to second crosspoint;

If there is no such signaling channel, then according to described detection, by network for these two crosspoints set up a special signaling channel and

Setting up a voice channel between two crosspoints to set up the calling between first and second users.

19. the crosspoint that is used to connect public telecommunication network and can connects user terminal comprises

A control device, this control device can detect from the foundation request of first user terminal that is connected to the related exchange unit to second user terminal that is connected to second crosspoint, and if there is no such signaling channel, then according to described detection, use signaling by public telecommunication network oneself crosspoint and other crosspoint between set up a special signaling channel, and between first and second user terminals, set up a voice channel to set up the calling between them.

20. be used to connect public telecommunication network and comprise at least two devices that can connect the crosspoint of user terminal, wherein each crosspoint comprises a control device or has the right to visit a control device, this control device can detect the request that second user terminal with being connected to second crosspoint of initiating from first user terminal that is connected to relevant crosspoint connects, and if there is no such signaling channel, then depend on described detection, use signaling by public telecommunication network oneself crosspoint and other crosspoint between set up a special signaling channel, and between first and second user terminals, set up a voice channel to set up the calling between them.