JP3226868B2 - ISDN terminal adapter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
ted services digital network) With respect to communication terminals, in particular, an ISDN communication terminal (hereinafter, referred to as a multi-point connection) connected to an ISDN basic interface having two B channels for user information transfer and one D channel for signal transfer.
ISDN terminal adapter).

[0002]

2. Description of the Related Art A multipoint connection is one ISD
One of the two terminal adapters connected to the N basic interface is, for example, an adapter that transmits and receives a large amount of data such as an ISDN video conference (hereinafter, referred to as an adapter a),
Adapters that send and receive relatively small amounts of data, such as data communications and fax communications, when other terminal adapters
Adapter b).
When the adapter a transfers data using two user information transfer B channels simultaneously, the terminal adapter b cannot receive a call. Conventionally, various methods and apparatuses have been proposed to eliminate such inconveniences.

A monitoring function is provided in the "ISDN composite terminal channel control method" (hereinafter referred to as "prior art document 1") disclosed in Japanese Patent Laid-Open No. 5-7257.
While the terminal adapter a is simultaneously using two B channels, it detects an outgoing / incoming / outgoing request from the terminal adapter b and releases the necessary channel to the terminal adapter b among the channels used by the terminal adapter a. ing.

An "ISDN communication terminal" disclosed in Japanese Patent Application Laid-Open No. 6-85954 (hereinafter referred to as "prior art document 2") discloses a method in which "when there is a response from the ISDN basic interface when there is no available channel at the time of calling at the terminal itself. In addition, by providing a `` vacant channel detection means for detecting the release of the channel used by other terminals '' and `` recall means for re-calling when a vacant channel is detected '',
The above-mentioned problem is eliminated.

[0005]

In the method of the prior art document 1, it is necessary to provide a monitoring function in addition to the terminal adapter a and the terminal adapter b, which complicates the device configuration and the signal reciprocation. There is a point. Further, in the device of the prior art document 2, when a self-terminal originates a call, the idle channel detection is started after a response indicating that there is no available channel from the ISDN basic interface, so that a useless call request and a response to the request are performed. was there.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the conventional apparatus. Among the multipoint-connected terminal adapters, at least one of the terminal adapters has a B channel management table, and always keeps the state of the ISDN line. An object of the present invention is to provide an ISDN terminal adapter which can monitor and update the contents of this table and can efficiently make and receive calls according to the contents of this table.

[0007]

Means for Solving the Problems That is, the ISD of the present invention
N terminal adapter, der if the same ISDN line multiple ISDN terminal adapter are connected
I, and B channel management table for storing the use status of the user information transfer B channels of the ISDN line, the constantly monitors messages on the ISDN line through the ISDN connections in the ISDN terminal adapter B
Means for updating the contents of the channel management table, the I
SDN is when receiving a call setup message to the terminal adapter the B unit for executing an incoming call process in accordance with the contents of the channel management table and said plurality of ISDN Terminal
ISDN terminating at least one of the null adapters
Provided on the same ISDN line.
ISDN terminal adapters are connected
Is one of the two ISDN terminal adapters
Terminal adapters send and receive in an ISDN video conference
Data communication with less data volume than transmitted data, F
ISDN terminal that sends and receives data such as AX communication
Data adapter that sends and receives data with a small amount of data.
Connect the B channel to the ISDN terminal adapter
Management table is provided,
Call setup for sending and receiving ISDN terminal adapters
The message is identical to its ISDN terminal adapter.
Other ISDN stations connected to the connection to the ISDN line
When the terminal adapter receives, the other ISDN
When two B channels are used in the terminal adapter
Determines whether one B channel can be disconnected,
In this case, disconnect one B channel and disconnect it.
The data amount is small using the B channel released by
ISDN terminal adapter to send and receive no data
Issuing a call message to an ISDN network
I do .

[0008]

Further, the ISDN line to which the plurality of ISDN terminal adapters are connected has two B channels for transferring user information and a D channel for transferring communication information.

[0010] The means for updating the contents of the B channel management table includes a call setup message sent from another ISDN terminal adapter connected to the ISDN line to the ISDN line network.
When a call setting acceptance message is transmitted from the network, a "use" flag is set in a channel use state column of a row of a corresponding B channel type in the B channel management table according to the contents of these messages, and a call number value column is set. Means for inputting a call number into another ISDN line connected to the ISDN line.
A call setup message is sent from the ISDN line network to the SDN terminal adapter, and the other ISD
When response messages are sent from the N terminal adapter, the "use" flag is set in the channel use status column of the row of the corresponding B channel type in the B channel management table and the call number value column is set in accordance with the contents of these messages. A means for writing a call number, a disconnection message is sent from another ISDN terminal adapter connected to the ISDN line to the ISDN line network,
When a release message is sent from the circuit network, the call number is obtained from the disconnection message, compared with the call number value in the B channel management table, and if they match, the "use" flag in the use state column of the line is reset. Means for performing the IS
When a disconnection message is sent from the ISDN network to another ISDN terminal adapter connected to the DN line, and a release message is sent in response to the disconnection message, a call number is obtained from the disconnection message and the B channel management table is obtained. And a means for resetting the "use" flag in the use state column of the row when the call number value matches the call number value.

[0011]

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. In FIG. 1, 1 is an ISDN terminal adapter, 2 is this device, and 3 is an ISDN network. For the same ISDN network 3, reference numeral 1 in FIG.
2, two ISDN terminal adapters are connected. The ISDN terminal adapter 1 is an ISDN terminal adapter (adapter a) for transmitting and receiving a large amount of data as in an ISDN video conference.
ISD that sends and receives a relatively small amount of data like X communication
It is assumed that this is an N terminal adapter (adapter b).

FIG. 2 is a block diagram showing a configuration example of the present apparatus 2 shown in FIG. 1. In FIG. 2, reference numeral 10 denotes an ISDN line,
2 is an ISDN connection unit, 13 is a D channel control unit, 14 is a B channel control unit, 15 is a B channel management table, 1
6 is a digital data control unit, 17 is an analog data control unit, 18 is a digital device connection unit, and 19 is an analog device connection unit. A digital terminal 20 connected to this ISDN terminal adapter 2 is connected to a digital device connection unit 18. Then, the analog terminal 21 is connected to the analog device connection unit 19.

The IS connected to the ISDN connection unit 12
The DN line 10 includes two B channels for transferring user information and one D channel for transferring communication information. The two B channels are called B1 channel and B channel.
There are two channels. ISDN connection 12 is channel B
1, B2 and D are separated and multiplexed, and the ISDN line 10
Interface connection operation with.

FIG. 8 is a format diagram showing the contents of the B channel management table 15. Reference numeral 81 denotes a row relating to the B1 channel, reference numeral 82 denotes a row relating to the B2 channel, and reference numeral 83 denotes a column indicating the use state of the channel. At this time, the one-bit memory of this column stores logic "1" (the flag is set), and when the channel is not used, the one-bit memory stores logic "0" (reset). . Reference numeral 84 denotes a column for storing the call number value in use of the channel when the flag in the column 83 is set.

The format of a message exchanged on the ISDN line 10 is described in ITU-T Recommendation Q.2. According to the format defined in 931, the data is transmitted on the D channel, separated by the ISDN connection unit 12, and used for updating the contents of the B channel management table 15 via the D channel control unit 13. The D channel control unit 13 performs D channel call control. The B channel control unit 14, the digital data control unit 16,
Analog data control unit 17, digital device connection unit 1
8. The operation of the analog device connection section 19 is the same as the operation of these parts in the conventional terminal adapter, and has no direct relationship in the present invention, so that the description is omitted.

FIG. 3 to FIG. 5 are sequence diagrams of messages exchanged on the ISDN line 10, and FIG.
FIG. 7 is a flowchart showing the steps of the operation in the ISDN terminal adapter 1. Hereinafter, the flow of the channel use operation in the present invention will be described with reference to FIGS.

Referring to FIG. 3, it starts from a state in which neither the ISDN terminal adapter 1 nor the present apparatus 2 uses the B channel. In a sequence 31, the ISDN terminal adapter 1 issues a call setup message to the ISDN network (3 in FIG. 1). The D channel control unit 13 temporarily stores the call number value of the call setup message. IS in sequence 32
The DN network 3 issues a call setting acceptance message and designates the B1 channel by the channel identifier. The D channel control unit 13 sets a flag in the column of row 81 and column 83 of the B channel management table 15 in FIG. 8 and writes the call number value in the column of column 84 of that row. Thereafter, after a call message in sequence 33, a response message in sequence 34, and a response confirmation message in sequence 35, communication on the B1 channel is performed.

Next, it is assumed that there is an incoming call to the ISDN terminal adapter 1. A call setup message is issued from ISDN line network 3 to ISDN terminal adapter 1 (sequence 36). Since the call setting message contains information on the used channel B2 based on the call number value and the channel identifier, the D-channel control unit 13 sets a flag in the column of row 82 and column 83 of the B-channel management table 15 in FIG. Then, the call number value is written in the call number value column 84 of that row.
Thereafter, a response message of sequence 37, sequence 3
8 and the communication on the B2 channel is performed. In this way, communication on the B1 and B2 channels is performed after the lapse of the sequences 31 to 38.

FIG. 4 shows that the ISDN terminal adapter 1 is B
It starts from a state in which communication is being performed on channels 1 and B2. The adapter 1 ends the communication on the channel B1, and the sequence 4
In step 1, a disconnection message is issued to the ISDN network 3. D
The channel control unit 13 acquires the call number from the disconnection message, compares the call number with the call number in the B channel management table, and when they match (assuming that they match with the call number of the B1 channel), resets the flag of that row. Sequence 42
The B1 channel is released through the release message of the sequence 43 and the release completion message of the sequence 43, and the ISDN terminal adapter 1 starts communication using only the B2 channel.
When the other terminal communicating with the ISDN terminal adapter 1 on the B2 channel terminates communication and issues a disconnection message via the ISDN network 3 (sequence 44), the D channel control unit 13 obtains a call number from the disconnection message. Then, the call number is compared with the call number in the B channel management table, and if they match (assuming that they match with the call number of the B2 channel), the flag in that row is reset. The B2 channel is released via the release message of the sequence 45 and the release completion message of the sequence 46, and the B channel becomes unused.

In the example shown in FIG. 5, it is assumed that two B channels are in use in the ISDN terminal adapter 1.
In a sequence 51, a call setting message is issued from the ISDN network 3 to the apparatus 2. This message is ISDN
It is also detected by the terminal adapter 1. ISDN terminal 1 issues a disconnect message when one of the B channels is open (sequence 52). For this message, the same processing as that for the disconnection message in the sequence 41 of FIG. 4 is performed in the present apparatus 2, and the B channel management table 15 is updated to indicate that the B channel is empty. When one B channel is released by the release message 53 and the release completion message 54,
The device 2 issues a call message to the ISDN line network 3 using the released B channel (sequence 55), and after the sequences 56 and 57, the device 2 can communicate.

In step S61 of FIG. 6, the apparatus 2
It is in a state of waiting for the reception of a call setting message from the DN line network 3. When the call setting message is received, the B channel management table 15 is checked. If any of the B channels is vacant, the normal incoming call processing is started. (Steps S62-S63
-S66), if there is no vacancy in the B channel, wait for a certain period of time, re-examine the B channel management table 15, and if a vacancy occurs, call using the vacant B channel (steps S64-S65). If there is no vacancy, the incoming call processing ends.

In step S71 of FIG. 7, the ISDN terminal adapter 1 is waiting for an incoming call from the ISDN line network 3 (waiting for receiving a call setup message). Processing is performed (steps S72-73-76). If two B channels are being used, it is determined whether disconnection of the B channel is possible. If possible, one B channel is disconnected (step S73). -74-75). If the B channel cannot be disconnected, the normal incoming call processing in step S76 is performed. In this case, the source of the call setting message is notified that there is no free line.

In the above description, the B channel management table is provided only in the present apparatus 2. However, the B channel management table may be provided in the ISDN terminal adapter 1.

[0025]

As described above, according to the present invention, the contents of the B channel management table 15 are constantly updated.
And another bus-connected ISDN terminal adapter 1
If a call setup message is received while two B channels are being used together, it is determined whether one B channel can be released. If possible, the B channel is released. Is quickly detected to enable communication.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of the present apparatus shown in FIG.

FIG. 3 is a sequence diagram showing an example of the progress of a message exchanged on the ISDN line 10 of FIG. 2;

FIG. 4 is a sequence diagram showing another example of the progress of a message exchanged on the ISDN line 10 of FIG. 2;

FIG. 5 is a sequence diagram showing another example when a message exchanged on the ISDN line 10 of FIG. 2 elapses.

FIG. 6 is a flowchart showing the operation of the present apparatus of FIG. 1;

FIG. 7 is a flowchart showing the operation of the ISDN terminal adapter of FIG. 1;

FIG. 8 is a format diagram showing contents of a B channel management table of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ISDN terminal adapter 2 This apparatus 3 ISDN line network 10 ISDN line 12 ISDN connection part 13 D channel control part 15 B channel management table

Continuation of the front page (56) References JP-A-10-13509 (JP, A) JP-A-3-72754 (JP, A) JP-A-5-7257 (JP, A) JP-A-11-68739 (JP JP-A-11-234424 (JP, A) JP-A-6-209357 (JP, A) JP-A-6-85954 (JP, A) JP-A-1-2311591 (JP, A) 63-199552 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04M 11/00-11/10 H04L 12/02 H04L 29/10

Claims (3)

(57) [Claims] 1. A case where the same ISDN line to a plurality of ISDN terminal adapter, and the B channel management table for storing the use status of the user information transfer B channels of the ISDN line, the ISDN terminal Means for constantly monitoring a message on the ISDN line via an ISDN connection unit in the adapter to update the contents of the B channel management table, and for controlling the B channel management when a call setup message to the ISDN terminal adapter is received means and said plurality of ISDN to perform incoming call processing in accordance with the contents of the table
ISDN of at least one of the terminal adapters
A terminal adapter is provided on the same ISDN line.
If adapters are connected, the two ISDN
Terminal adapter of one of the terminal adapters
Is smaller than the data transmitted and received in ISDN video conferences.
Data communication with small data volume, data such as FAX communication
ISDN terminal adapter for transmitting and receiving
ISDN terminator for sending and receiving small data
The BDN management table is provided in the adapter, and the ISDN module for transmitting and receiving the small amount of data is provided .
The call setup message to the terminal adapter
Connect to the same ISDN line as the N terminal adapter
Connected to another ISDN terminal adapter.
The other ISDN terminal adapter
When using two B channels, disconnect one B channel
Judge whether it is possible or not, and if possible, use one B channel
B channel that has been cut and opened by the cut
I that transmits and receives the small amount of data using
The SDN terminal adapter calls the ISDN line
ISDN terminal that emits a message
Dapta. 2. The ISDN terminal adapter according to claim 1,
A plurality of ISDN terminal adapters.
Is connected to the user information transfer B
Two channels and a D channel for communication information transfer
Characterized by comprising an ISDN terminal adapter
Ta. 3. The ISDN terminal adapter according to claim 1,
And updates the contents of the B channel management table.
The new means may be another ISDN terminator connected to the ISDN line.
Call setup message from ISDN line network
Is sent, and in response to this, the call setup
When these messages are sent,
According to the contents, the corresponding B channel in the B channel management table
"Use" flag in the channel use status column of the line of the channel type
Means for setting and writing a call number in a call number setting column, and another ISDN terminal connected to the ISDN line.
Call setup message from ISDN network to null adapter
The other ISDN terminal responds
When a response message is sent from the adapter,
According to the content of the message, the B channel management table
In the channel usage status column of the row of the corresponding B channel type
Set the “use” flag and write the call number in the call number setting column.
And another ISDN terminal connected to the ISDN line.
Disconnect message from ISDN network to null adapter
Is sent, and an open message is sent from the ISDN network.
When the message is sent, the call number is
Is obtained, and compared with the call number value of the B channel management table.
If they match, the “usage” flag in the
Means for resetting the network, and another ISDN terminator connected to the ISDN line.
Disconnect message from ISDN network to null adapter
Is sent, and a release message is sent in response to this.
The call number from the disconnection message
Compare with the call number value in the channel management table and if they match
How to reset the "use" flag in the usage column of the row
ISDN terminal adapter having steps
Puta.