JPH04207294A - Automatic b-channel vacancy standby system in isdn - Google Patents

Abstract

PURPOSE:To surely execute re-outgoing by a user who issues a call by informing the presence of a null B-channel at a time when it occurs from a network side to a digital terminal set in a standby state. CONSTITUTION:When a B-channel is busy at the time of issuing the call from the digital terminal 30, a message of outgoing cutoff is sent from an exchange 10 to the terminal 30. At this time, a call state is transited to an automatic outgoing start-up inquiry state. When the user issues an automatic outgoing request, the terminal 30 is transited to an automatic outgoing standby state, and a B-channel vacancy information request is sent to the exchange 10. When the null B-channel occurs, the exchange 10 reads out a terminal identification number from a registered terminal memory column with the highest priority, and sends an information message to a terminal side. Thereby, automatic re- outgoing can be performed when the null B-channel occurs.

Description

[Detailed description of the invention]

[Summary of the Invention] I Related to the outgoing connection processing of a plurality of digital terminals connected point-to-multipoint to a digital exchange equipped with an SDN compatible function, in particular the B channel used for voice or data communication. Regarding the free automatic standby system, if all B channels are in use when a call is made from a digital terminal, the user who made the call will not be able to make a re-call when the B channel becomes free. The purpose is to ensure that calls can be made from any one of multiple digital terminals that are point-to-multipoint connected to a digital exchange equipped with I5DN capabilities and that use the B channel for user data communications. If all B channels are in use, the terminal side function continues to make outgoing connection requests until a free B channel becomes available. The configuration includes a network side function for notifying the digital terminal.

[Industrial application field]

The present invention relates to outgoing connection processing of a plurality of digital terminals connected point-to-multipoint to a digital exchange equipped with an I5DN compatible function, and in particular,
This invention relates to an automatic standby system for a B channel used for data communication. When connecting digital terminals point-to-multipoint to a digital exchange equipped with l5DN compatible functions, multiple digital terminals can be connected to one subscriber line (up to 8
terminals), and calls can be made arbitrarily from each of these multiple digital terminals. In the case of 15DN, for example, if it is a basic interface, the B channel for voice and data communication, that is, user data communication, is 2 channels (2B+D;D
is a control channel), and if it is a primary group interface, a plurality of B channels can be used for user data communication, such as 23 B channels (23B+D). The acquisition order of B channels is based on the D channel contention control method defined in the ■ series international standards.

[Conventional technology]

By the way, when a call is made from any digital terminal, all B channels may be in use and there may be no free B channels. In the conventional terminal control process using a digital exchange equipped with an I5DN compatible function, when all B channels are occupied in this way, the digital exchange sends a call disconnection message to the digital terminal, and the digital terminal receives this and disconnects the call. Outgoing calls are disconnected. For this reason, conventionally, when a person attempting to make a call encounters a situation in which all B channels are occupied, he or she visually detects the occurrence of an empty B channel by looking at the usage status of other digital terminals, or The system predicts that the B channel will occur and retransmits after a predetermined period of time.

[Problem to be solved by the invention]

However, in cases where multiple digital terminals are installed in different rooms or on different floors and are connected to the same subscriber line (this situation is relatively common in L5DN), the digital terminal during a call may other callers cannot see the status of the caller. For this reason, users cannot visually check whether the B channel is free, and if they encounter a situation where all channels are blocked as described above, the user trying to make a call will have to repeat the process over and over again until they are able to make a call. You have to try to send a message, which makes it very inconvenient to use. In view of the above points, this invention provides that if all B channels are in use when a user makes a call from a digital terminal, then when a B channel becomes available, the user who made the call The purpose is to ensure that the retransmission of the information is possible.

[Means to solve the problem]

In order to solve the above-mentioned problems, this invention provides a point-to-multipoint connection to a digital exchange equipped with an I5DN compatible function, and calls are made from any one of a plurality of digital terminals that use the B channel for user data communication. If all B channels are in use, the digital terminal will have a function to continue making outgoing connection requests until a free B channel becomes available, and will also send a notification to that effect when a free B channel becomes available. The network side is provided with at least a function to notify the digital terminal that is waiting for a call.

[Effect]

If the digital exchange receives a call from a digital terminal and all B channels are in use, the digital exchange detects this and sends a call request rejection notification to the digital terminal that issued the call request. When the digital terminal receives this notification, it temporarily disconnects the outgoing call, but enters a standby state waiting for the B channel availability notification from the digital exchange and continues to make outgoing connection requests. Thereafter, when a vacant B channel occurs, a B channel vacant notification is sent from the digital exchange to the digital terminal that issued the call request or to all digital terminals connected to the same subscriber line. Upon receiving this B channel availability notification, the digital terminal makes a determination and drives a notification means to display a notification to that effect on a display, for example, or to notify that effect by voice. Using this notification means, the caller can detect that the B channel is vacant and can easily make a re-call. Or B
It is also possible to automatically make a re-transmission upon receiving a channel availability notification.

【Example】

FIG. 1 shows the configuration of an embodiment of the present invention, and shows an example of a connection configuration between a digital terminal and a digital exchange. In the same figure, 10 is a digital exchange, a central control unit!
f11, a digital subscriber line control bag W2°, a time division type distribution stage communication path 12, a time division type concentrator stage communication path 13, and a digital subscriber circuit 14. 15 is an 15DN line, and in this example, communication is performed using the basic interface +28 (Bl, B2) +D+. Reference numeral 16 denotes a network termination device, through which a plurality of digital terminals 30 (up to eight) can be connected. In the digital exchange 10, what is shown surrounded by dotted lines in the figure is a block diagram showing the functions of the digital subscriber line control device 20, which includes a communication control section 21, a call control section 22, and a B channel management section. 23 and a B channel management table 24 are provided. The B channel management table 24 contains 8 of the B channels.
A column 41 for storing information indicating whether channel 1 is available or not, and a column 4 for storing information indicating whether channel B2 is available or not.
2, a column 43 for storing the number of B channel vacancy requests from the digital terminals 3o, and 8 terminal storage columns 4 for sequentially registering and storing the identification numbers of digital terminals that have made vacancy notification requests.
It consists of 4. Further, in this example, the digital terminal 30 includes functional blocks as shown surrounded by dotted lines in the figure. That is, the digital terminal 30 includes a communication control section 31, a call control section 32, a display control section 33, a tone control section 34, and a key control section 35. Next, some examples of automatic standby systems for empty B channels according to the present invention will be described with reference to FIG. 1 and diagrams showing respective sequences. FIG. 2 is a diagram showing the sequence of the first embodiment. Digital exchange 10 in the sequence described below
Information transmission between the digital terminal 30 and the digital terminal 30 is performed using the D channel. First, when a user performs a call operation on one of the digital terminals 30, the digital terminal 30 sends a call request message 5.
Send ETUP to digital exchange 10. The digital exchange 10 receives this outgoing request at the digital subscriber circuit 14 and sends it to the digital subscriber line control device 20. Then, in the digital subscriber line control device 20, this is received by the call control unit 22 via the communication control unit 21, and the B channel management unit 23 stores the B channel management table 2.
With reference to columns 41 and 42 of No. 4, it is determined whether there is an empty B channel. When there is an empty B channel, the digital subscriber line controller 20 sends CALL PROC (CALL PROCEEDI) which is a response to the outgoing request.
NG, notification that call setup is in progress) or 5E
TUP ACK (SETLIP ACKNOWLEDG)
E; Confirmation for 5ETUP +, 1m) Send to the digital terminal and continue the outgoing connection procedure. On the other hand, when there is no free B channel and both channels are occupied, the digital subscriber line controller 20 sends a call disconnection request message REL COM (RELIEAS
E COMPLETE) is sent to the digital terminal 30, and the digital terminal 30 disconnects the call. However, when the key for requesting B channel availability notification is pressed on the digital terminal 30, this is detected by the key control unit 35, and the call control unit 32 transmits the B channel availability notification request message via the communication control unit 31 to INFO ( INFOMA
TION, additional control information) is included in the message and sent to the digital exchange 10. Digital subscriber line control device for digital exchange 10! [20
In response to this B channel availability notification request, the B channel management unit 23 updates column 4 of the B channel management table 24.
3, the number of B channel free requests is counted up by "1", and the digital terminal 30 that issued the free notification request is written in the column with the lowest number of the eight terminal storage columns 44.
Register by writing the identification number. Furthermore, the digital exchange 1O sends to the digital terminal 30 information indicating that the B channel availability notification request has been accepted, included in the INFO message. At this time, the INFO message includes information identifying the digital terminal that issued the availability notification request. When the digital terminal 30 receives this B channel availability notification request, the display control unit 33 displays this on a display (not shown). Thereafter, when the call control unit 22 detects that the B1 or B2 channel has been released, the B channel management unit 23 rewrites the information that the column 51 or 52 of the B channel management table 24 is empty. Then, the B channel management section 23
Then, by checking the B channel management table 24 and checking the number of B channel free requests, it is determined whether there is a free notification request. Then, when it is detected that the number of vacancy requests is "1" or more, that is, the existence of a vacancy notification request, the call control unit 23 stores the oldest request (this is TEI (n) in the terminal storage column 44). n (1, 2, ·) young ones)
A B channel availability notification is sent to the digital terminal using an INFO message. At this time, the terminal identification number is obtained from the terminal storage field and included in the INFO message. Then, in the digital exchange 10, the number of vacancy notification requests in the B channel management table 24 is decremented by 1, the terminal memory column that sent the notification is cleared, and the remaining terminals to which vacancy notification requests are registered are cleared. Sort the memory columns in order of priority. In the digital terminal 30, in response to this INFO message, the call control unit 32 controls the display control unit 33 and the tone control unit 34, and the display control unit 33 indicates that the B channel is available on the display (not shown) of the digital terminal 30. message is displayed, and the tone control unit 34
As a result, a sound is emitted from the speaker to notify that the B channel is available. As a result, the user can easily know whether the B channel is available and can easily make a retransmission. Note that when the digital terminal 30 issues a B channel availability notification request, it is possible to specify that the availability notification be sent not only to the digital terminal currently making a call, but also to all digital terminals. This is because when a user moves from the digital terminal that made the call, there is a need to be able to make the call from another terminal. In this case, the terminal storage column 44 of the B channel management table 24 of the digital exchange 10 stores, for example, H=7F instead of the terminal number of the digital terminal that made the call. When the digital exchange 10 sends a vacant notice to the digital terminal side, if this data is stored in the highest priority terminal storage column 44, this means that a message in broadcast format will be sent. Therefore, vacancy notifications will be sent to all digital devices. A B channel availability notification request from the digital terminal 30 (all terminals can also be specified) is sent via message 5E when making a call.
You may also include it in the TUP and send it. In other words, if the B channel is occupied, a notification of availability is requested at the same time as the digital terminal 30 makes a call. FIG. 3 is a diagram showing the sequence in that case. When issuing a call request from the digital terminal 30, for example, after inputting a telephone number, a key operation is performed to receive a service of requesting availability notification. Then, the digital terminal 30 sends an outgoing request message 5ETUP including a vacancy notification request to the digital exchange 10. In this case, the vacancy notification request acceptance message from the digital exchange 10 is transmitted while being included in the message REL COM that once rejects the call from the digital terminal. The rest is the same as the sequence in FIG. 3. Furthermore, if the B channel is occupied at the time of a call, it is also possible to have a service contract with the station that allows it to receive notification of availability, and to ensure that the B channel availability notification request is included in the message 5ETUP of the call request. In this case, key operations for requesting availability notification become unnecessary. In the example above, the user learns of the availability of channel B through the display or voice and then performs the operation to make a re-call, but the digital terminal that receives the availability notification automatically makes the call. You can also do that. FIG. 4 is a diagram showing the sequence in that case. In this example, when a call is made from the digital terminal 30, if the B channel is blocked, a message REL CON to disconnect the call is sent from the digital exchange 10 to the digital terminal 30, but the digital terminal When 30 receives this message, it inquires via display or voice to activate automatic calling. At this time, the call state transitions to an automatic call activation inquiry state. Then, when the user performs a key operation to request an automatic call, the digital terminal 30 transitions to an automatic call standby state and sends an INFO B channel availability notification request to the digital exchange 10.
Send it in a message. Upon receiving this message, the digital exchange 10 increments the number of B channel free requests by "1" in the same manner as described above, and stores the digital terminal in the high priority column of the unregistered terminal storage column 44. Register your identification number. Then, when a B channel becomes vacant, the digital exchange 10 decrements the B channel vacant request number column of the B channel management table 24 by "1", and also reduces the number of B channel vacant requests in the B channel management table 24, and also reduces the number of B channel vacant requests by 1, and the terminal memory column with the highest priority among the registered terminal memory columns 44. The digital terminal identification number is read from the digital terminal, and a vacancy notification message to which the identification number of the digital terminal is attached is sent to the digital terminal side. Then, the terminal memory column of the digital terminal in the B channel management table 24 is cleared, and the terminal memory columns in which the digital terminal with the notification request is registered are sequentially filled in the higher priority order. When the digital terminal specified by the B channel availability notification message receives this availability notification message, it displays this on its display and also notifies it by voice. Then, the automatic dialing means (not shown) that stores the information at the time of the previous call when the call was rejected performs an automatic call operation, and sends a call request message 5ET.
UP is sent to the digital exchange 10. As described above, automatic re-transmission can be performed when the B channel becomes vacant. In the above example, if the B channel is blocked when a call is made from a digital terminal, the digital exchange 10 will temporarily
Message REL CO rejecting the call request and disconnecting the call
N is sent to the digital terminal, but the digital exchange 10 can also suspend calls from the digital terminal when the B channel is occupied, as in the following example. FIG. 5 is a diagram showing the sequence in that case. That is, in this example, when there is a call from the digital terminal 30 and the B channel is occupied, the digital exchange 10 sends an inquiry about pending call to the digital terminal 30 as an INI'0 message. On the other hand, if the user does not perform a key operation to request call hold on the digital terminal 30, the digital exchange 1
A message RELCOM for disconnecting the call comes from 0, and the digital terminal disconnects the call. On the other hand, when the user performs a key operation to request a call hold, the digital terminal 30 sends the call hold request to the digital exchange 10 as an INFO message. In response to this request, the digital exchange 10 sends the call control unit 22
Then, the state changes to the call pending state. Then, the call pending acceptance is sent to the digital terminal 30 as an INFO message. In response to this, the digital terminal 30 sends the digital exchange 10
The timer for waiting for a response to an outgoing request message from is switched to a longer time than usual. This response waiting timer is normally 4 to 10 seconds, and if no response message is received from the digital exchange 10 within this time, the call is disconnected. Then, send the message of hold reception to the digital terminal 30.
When the request is received, the response waiting timer time is changed to, for example, 90 seconds. When the digital exchange 10 detects that the B channel is vacant during the hold, it sends a response message CA to the outgoing request message 5ETUP to the digital terminal that made the hold request.
Send LL PROC or 5ETUP ACK. The digital exchange 10 then continues the operation at the time of the call request (call connection operation). That is, the response message is CA
In the case of LL PROC, since the telephone number of the other party has been received, the digital exchange 10 continues the call connection operation. When the response message is 5ETUP, it waits for input of the subscriber number of the other party from the digital terminal 30 and continues the call connection operation. As described above, in this example, B
If a channel becomes vacant, the user's call will definitely continue and be answered. FIG. 6 shows another example of the automatic transmission sequence when the B channel is empty. In this example, when a call from the digital terminal 30 is rejected by the digital exchange 10, the digital terminal 30 automatically repeats the call operation at fixed timer intervals. Therefore, if the B channel becomes available, the call will be accepted. Note that all the above examples are based on the basic interface (2
B+D), but the linear group interface (2
It goes without saying that the present invention can also be applied to the case of 3B+D). Furthermore, the digital exchange of the present invention can of course be applied to a private branch exchange of a PBX, rather than a person on the central office side.

【Effect of the invention】

As explained above, according to the present invention, if the B channel is occupied when a call is made from a digital terminal, the digital terminal becomes a standby state and notifies this by a vacant notification from the digital exchange. Therefore, the user can easily perform a re-transmission operation based on this notification. Additionally, the digital terminal can automatically make calls based on availability notifications from the digital exchange.
Easy to use for users. In addition, even if the B channel is occupied, by making a call hold request, the call will not be disconnected, and when the digital switch detects that the B channel is free, the digital switch will automatically continue the call. I do. Therefore, if the B channel becomes vacant while the call is on hold, the user's call request will definitely be accepted.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an example of a connection configuration between a digital exchange and a digital terminal, and FIGS. 2 to 6 are diagrams each showing a sequence of an example of the present invention. 10; Digital exchange 15.18 DN line 20; Digital subscriber line control device 23; B channel management section 24; B channel management table 30; Digital terminal 42; Call control section 43: Display control section 44; Tone control section 45; Key Control unit patent applicant Fujitsu Limited Digital Utility Consultant
Interchange 7.1 block 1r warm f! Example j Sequence Fig. 3 Fig. 3/1 Sequence with 1 Hi Fig. 4

Claims (4)

[Claims] (1) When a call is made from any of the digital terminals that are connected to multiple subscriber lines housed in a digital exchange equipped with ISDN compatible functions and communicate using the B channel, all B channels are used. If a free B channel is available, the digital terminal is provided with a means for continuing the outgoing connection request until a free B channel is available, and at least a means for notifying the digital terminal waiting for a call to that effect when a free B channel becomes available. ISD provided in the digital exchange
B channel free automatic standby system in N. (2) If a digital exchange equipped with an ISDN compatible function receives an outgoing call request from a digital terminal while all B channels are in use, the outgoing call request will be rejected, and then the B channel will become vacant. At the time, a means is provided to notify the digital terminal that made the call request of the availability of the B channel, and the digital terminal receives the notification of the availability of the B channel from the digital exchange and informs the digital terminal of the availability of the B channel. 2. The B channel free automatic standby system in an ISDN according to claim 1, further comprising: a notification means for notifying the user; and the notification means prompts the user to make a call. (3) When the digital exchange receives an outgoing call request from a digital terminal while all B channels are in use, the digital exchange temporarily rejects the outgoing request, and then, when B channels become vacant, at least the above Means is provided to notify the digital terminal that made the call request of the availability of the B channel, and the digital terminal includes means for storing that the call request has been rejected, and a notification of the availability of the B channel from the digital exchange. 2. The B channel free automatic standby system in an ISDN according to claim 1, further comprising means for making an automatic call request again in response to the request. (4) When a call is made from any of the digital terminals that are connected to multiple subscriber lines housed in a digital exchange equipped with ISDN compatible functions and communicate using the B channel, all the B channels are used. If there is a call request from a digital terminal while all B channels are in use, the digital exchange automatically waits until a free B channel becomes available. If there is, we will put the call on hold and
A means is provided to notify the digital terminal of a response to the outgoing request when the B channel becomes vacant during the hold, and the digital terminal receives the message of acceptance of the outgoing call request from the digital exchange, and the digital exchange responds to the outgoing request. A B channel free automatic standby system in an ISDN comprising means for extending the timer time of a timer for waiting for notification of a response from an ISDN.