JPS6346840A - Communication connecting and controlling system for isdn - Google Patents

Abstract

PURPOSE:To attain various communication between different kinds of terminal equipments by providing a communication management section modifying information between a terminal equipment and a layer and providing two information transfer lines so as to use them depending on the content of information. CONSTITUTION:In giving a primitive for the communication control to a communication management sections l, 4 from a terminal equipment 1.1 via an interface A1.2, the message of a corresponding layer 3 is selected and the processing of the corresponding layer 3 is requested to the processing section 1.6 of the layer 3. The processing section l.6 uses a requested message as a primitive to send it to the processing section 1.11 of the layer 2. The processing section 1.11 applies formatting to the received information in accordance with the CCITT recommendations and sends the result to the processing section 1.5 of the layer 1. The processing section 1.5 converts the received information into an electric signal and sends the signal to an exchange 1.7. The signal from the exchange l.7 is fed to the terminal equipment 1.1 via an opposite path to that above. After the end of setting of a channel, the user data of line exchange type is sent/received via the interface 1.3 and that of the packet exchange type is transmitted/received via an interface A.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a communication connection control method for performing various communications between terminals having Layer 4 or higher functions using ISDN, and particularly relates to a communication connection control system that uses ISDN to perform various communications between terminals having functions of layer 4 or higher. ISD that allows various communications between
The present invention relates to a communication connection control method of N.

(Prior Art) Generally, when transmitting and receiving voice, a telephone terminal is connected via a telephone line, and when transmitting and receiving data, a data terminal is connected via a data line. In other words, each terminal device such as a telephone or a data terminal is connected one-to-one with a communication function such as voice communication or data communication, and when using multiple terminal functions, each communication function is I was setting up a g line.

I SDN (Int, erated 5ervi
In the CES Digital Network, a user can perform voice, image, facsimile, and other communications using circuit-switched and packet-switched communication functions via a single subscriber line.

The international standard protocol for ISDN is defined based on the O5T reference model, and is C(:ITT (Com1
teConsultajif International
nal Telegraphique eLTcl
ephonique (International Telegraph and Telephone Advisory Committee). In the 051 reference model, the functions necessary for communication between terminals are layered into seven layers, and each layer (
The functions to be realized for each layer (called primitives) and the information to be sent and received between each layer (called primitives) are defined, and among these, the functions of layers 1 to 3 are communication functions, and the functions of layer 4 are
~Equivalent to Layer 7 function or terminal function ``4''. ISD
The international standard protocol of N is the functions of layers 1 to 3 realized in ISDN, between layers 1 and 2, and between layers 2 and 3.
It defines the primitives in between. I SDN or provision 1-
By using three functions, multiple terminal functions can be used with one communication line.

(Problems to be Solved by the Invention) By providing the ISDN communication function through a common interface regardless of the type of terminal function or communication function, the terminal function and the ISDN communication function can be easily combined.

However, this has the following problems, and IS
There is still no example of implementation in which various terminal functions and various communication functions such as circuit-switched packet switching are combined in a DN.

(1) Leia 3. Information that needs to be processed differently, such as control information and packet-switched user data that require processing in Layer 2, and circuit-switched user data that does not require processing in Layer 3 and Layer 2, is shared between the terminal and the IS.
It is necessary to send and receive information between parts that control DN communication.

(2) The ISDN international standard protocol does not define primitives between ISDN layer 3 and layer 4 or higher.

Furthermore, even if the primitives specified in the O5I reference model are applied between Layer 3 and Layer 4, these primitives alone will not be sufficient when using the circuit-switched communication function, which is one of the communication functions of ISDN. etc. is insufficient.

(3) Zarani I SDN can provide all the common communication functions such as voice and facsimile, but communication between Layer 3 and Layer 4 is still necessary, even though there are communication functions that cannot be supported by some terminals. However, it is extremely inefficient.

(Means for Solving Problems 1-1) The present invention has been made to solve the problems of the prior art described above. The purpose is to provide a three-way connection;

The first feature of the present invention is to provide a communication management unit for converting signals between the terminal and layer 3, and to
A first information transfer path for transferring information for controlling communication and discrete-switched user data, etc. between the terminal and Layer 1, and a first information transfer path for transferring circuit-switched user data, etc. between the terminal and layer 1. The purpose of this invention is to enable various types of communication between different types of terminals by providing respective transfer paths for the second information.

The second feature of the present invention is that the communication functions that can be supported by the terminal are registered in advance in the communication management unit, and when the receiving side requests the start of communication, the communication functions included in the message of the start request are registered in advance. It compares the information indicating the communication request with the information registered in the communication management department to determine whether it can respond to the communication request from the calling side, and if it can respond, it notifies the terminal of that information and responds accordingly. If this is not possible, the communication request is denied to the calling party.

(Structure and operation of the invention) The present invention will be described in detail below using the drawings.

(Embodiment 1) FIG. 1 shows a first embodiment of the present invention, and is a block diagram for explaining a communication connection control method. In the figure, the dashed lines (----1~→) and the dashed-dot lines (-m--→) indicate the flow of control information and packet-switched user data signals on the transmitting side and the receiving side, respectively, and the dashed lines < ------
−1→) is the circuit-switched user data signal ffjE,
h, and the numbers in circles indicate the order in which the signals flow. The terminal has terminal functions of layer 4 or higher of the O3I reference model. There are two interfaces (interfaces A1.2 and B) for transmitting and receiving different types of information, which is one of the features of the present invention, between the terminal "h" and the part that controls ISDN communication. In addition, a communication management section that performs mapping between primitives and layer 3 processing is provided. An interface A1.2 is provided between the communication management section L and the terminal, and transmits and receives information for controlling communication and packet-switched user data as primitives. In addition, an interface B1.3 is provided between the terminal and a section that performs layer 1 processing (referred to as a layer 1 processing section), and transmits and receives user data in a circuit-switched manner. The communication management section is the part that performs Layer 3 processing to control communication.
A part 1.8 (referred to as a conversion table part) that stores the correspondence between messages sent and received between exchanges 1.7 and primitives (referred to as a layer aco processing part), and a part 1.8 (referred to as a conversion table part) that performs processing to send primitives sent from a terminal to a corresponding terminal. It consists of a part to be carried out (referred to as a conversion part).

The RAYAco processing unit controls the start and end of packet communications and communications, and performs processes such as transmitting and receiving information necessary for this purpose as messages to and from the exchange 1.7. The processing of the ReaCo processing unit has already been specified in CC:ITT Recommendation 1.451, and devices based on this specification have been developed, so this technology is already well known.

A subgroup that performs Layer 2 processing (referred to as the Layer 2 processing unit) receives information sent as primitives from the subgroup (referred to as the management unit) that performs data link setup and release, error recovery processing, etc., and the Layer 2 processing unit L. CITT Recommendation 1.
441 and sends it as a primitive to the layer 1 processing section (referred to as the transmitting section),
It consists of a partial plate (referred to as a receiving section) that deformats the information sent as a primitive from layer 1 processing section 2 to layer C based on ITT recommendation 1.441 and sends it as a primitive to the layer aco processing section. The exchange performs processing to ensure that information sent and received between the two is transferred without error. Leia 2 processing section Ritan's processing, Leia 2
- Primitives between 3 are defined in CCITT Recommendation 1.441. A device based on C(:ITT Recommendation 1.441) has also been developed, and this technology is already known.

The layer 1 processing unit L' is a partial plate (MtJX/ (referred to as DMUX department)
, consists of a part (referred to as a conversion circuit part) that converts information into an electrical signal compliant with the transmission method of Indoor Bus 1.16,
Sends and receives information to and from the in-house bus. The processing of the layer 1 processing section and the primitives between layer 2 and CCI
Specified in TT Recommendations 1.430 and 1.431.

Devices based on CCITT Recommendations 1.430 and 1.431 have also been developed, and this technology is also already known.

A home bus service is a communication line within a subscriber's home, and includes network termination equipment 1. +8, which is connected to switchboard 2 via subscriber line 1.19. The in-home bus is a 64K network that transfers circuit-switched user data and packet-switched user data.
Multiple communication channels with a transmission capacity of 64bps (called B channel) and one communication channel with a transmission capacity of 64bps or 16Kbps (called D channel) that transfers communication control information and packet-switched user data. Become. These communication channels are time-division 9
This is achieved by layering 7 layers.

Next, the flow of signals will be explained.

Terminal 3. When a primitive for communication control sent from A1.2 via interface A1.2 enters the conversion section of the communication management section, the corresponding layer 3 message is selected based on information from the conversion table section. Then, the sending of this message and the corresponding Layer 3 processing are requested to the Layer 3 processor. The lay-a-co processing unit 1 uses the requested message as a primitive.
．． Send to 11. The layer 2 processing unit L2 formats the received primitive information in accordance with CCrTT Recommendation 1.44] and sends it as a primitive to the layer 11A processing unit 11s1.5. Laia 1 processing department"
The received primitive TN information is converted into an electric signal according to the transmission method of the local bus, and sent to the exchange via the D channel.

Conversely, the electrical signal sent from the exchange 1.7 via the D channel is converted by the layer 1 processor L and is sent as a primitive to the layer 1 processor. The lay-aware processing section then deformats the received primitive information in accordance with CCITT Recommendation 1.441, checks for errors in the information, and if there is no error, uses the information as a primitive and transfers it to the lay-aco processing section. Send to 'shi'. The relay processing unit ``SHI'' performs processing according to the message sent from the ``Switchboard'' and sends this message to the ``Converter'' of the communication management unit ``L''. The conversion section selects a corresponding primitive based on the information in the conversion table section and sends the selected primitive to the terminal via the interface A1.2.

When the communication path setting for user data is completed and user data is to be sent and received, the terminal determines the communication method, and the circuit-switched user data is sent to the packet-switched type via interface B1.3. User data is sent and received as a primitive via the interface A1.2.

After the terminal sets up a communication path and sends and receives user data,
Each procedure for releasing a communication channel is shown below.

FIG. 2 is a diagram showing a communication connection control procedure according to the present invention. Messages sent and received between the Layout Aco processing unit and the exchange L are handled by the Layout processing unit (: CITT
A71 Notification 1.441, the data is sent and received via the Layer 1 Processing Unit L, or the Layer 1 Processing Unit L in FIG. Represent messages as being sent and received between them.

Furthermore, the description of the internal processing of the communication management unit L will be omitted.

(1) Setting up a Δpath The originating terminal port sends a primitive 2.3 ((:0NNEfl:T-request
) will be sent to the Communications Management Department. The communication management unit 1 analyzes the request and requests the RIA processing unit 2 to send a corresponding message. The "RAI Aco processing unit L" sends messages 2 and 6 (SETtlP messages) requesting the start of communication to the exchange port. After receiving this message, exchange h' sends a 5ETUP message L' to request the communicating party to start communication.

The receiving side's Reiaco processing unit ``Niji'' receives the 5ETUP message and performs Layer 3 processing. Primitive 2 that indicates that a connection request has been made by the communications management department.
．． 11 (referred to as CONNECT-indication) through interface A2. +2 to the terminal pan. In order to respond to the request, the destination terminal 2.13 uses a primitive 2.14 (CONNE) that responds to the connection request.
CT-response) is sent to the Communications Management Department. The communication management section 2.10 sends the corresponding message L±5 (CONNECT message) to the switching machine.

In the international standard protocol of ISDN, C0N is sent from the destination side.
5EC: Connection of the communication path is completed when the T message 2.15 is received, so if the destination side sends user data to the communication path immediately after responding, or if the T message is lost to 0NNE, the information becomes invalid. Sending can occur. To prevent this, the international standard protocol for ISDN uses C0NNECT ACK to notify the called party that the communication path has been set up.
Since message 2.16 is provided, after receiving this message, it is necessary to notify the destination terminal that the communication path has been set up. However, in the 051 model, there is no primitive for this purpose.

Therefore, in the present invention, a primitive concavity (READY-indication
), and the destination terminal starts sending and receiving user data after receiving this primitive.

The exchange sends a C0NNECT ACK message to the destination side, and also sends a C0NNE (:T message 2.18 to the origination side. Communication management department mouth of the origination side) received from the RIAco processing unit. primitive 2.19 (C:ON) indicating that the connection request has been confirmed.
NECT-confirm) and notifies the originating terminal that the communication channel setup is complete, thereby establishing a communication channel between the terminals.

(2) In the case of user data 2.20, which is a line-switched type of user data transmission/reception, both the originating and terminating sides send user data to interface B2.21.2.
．． 22. On the other hand, in the case of packet-switched user data, a primitive 2.23 (referred to as DATA-request) requesting data transmission is sent from the originating terminal to the communication management department via interface A, and is sent here. The data packet is converted into an L-edited data packet and transferred to the destination side via a large switch. The data packet 2.25 that has arrived at the destination side is processed by the communication management department of the destination side using a primitive 2.26 that notifies the arrival of the data.
(It is converted into 9 called DATA-indication and sent between the destination terminals via interface A2.12.

(3) Release of communication channel A terminal that terminates communication sends primitive 2.27 (DISCONNEcT-reque) requesting disconnection of the communication channel.
st) is sent to the communication management section via interface A2.2. The communication management unit "h" sends a message "h" (DISC: 0NNE[l:T message) to request disconnection of the communication path to the exchange for this primitive giant. Exchange h disconnects the communication path and sends a DISCONNE[l:T message hη to the other party.

The communication management unit on the side to be disconnected indicates that the communication path has been disconnected by sending primitives 2 and 30 (D
15CONNECT-indication) to notify the terminal to be disconnected.

After this, in order to complete communication termination processing, a RELEASE message and 1
硅LEASE (:0) Send and receive APLETE messages.

(Embodiment 2) Next, initial settings and communication function selection, which are the second feature of the present invention, will be explained.

FIG. 3 is a diagram for explaining a method of selecting compatible communication functions according to a second embodiment of the present invention. In this figure, the terminal layer, communication management section, and layer coder processing section are the same as those in FIG.

In ISDN, various communication functions such as circuit-switched communication and packet-switched communication are provided via one subscriber line, so when a request is made to start communication on the receiving side, Analyze information indicating requested communication capabilities;
It is necessary to judge whether or not the request can be met.

Therefore, the present invention newly adds primitive 3.4 (STAT
-request) is provided, and as an initial setting, this primitive is used to notify the communication management section 2 of the communication functions that can be supported by the terminal in advance, and this information is stored in the register section 2.

When a TOP message is received and a request is made to start communication, the information contained in the message indicating the communication function and the information about the communication function that the terminal can support stored in the register section L are displayed. Compare with. If possible, it sends primitive 2 to the terminal via interface A, indicating that a connection request has been made. On the other hand, if it is not possible to respond, it requests the RAYA processing unit to ignore or reject the communication start request, and notifies the sending side of this information.

(Application Example) Below, a case will be described in which communication between personal computers is performed using the first and second embodiments of the present invention.

Table 1 shows the primitives provided for using the communication functions of ISDN and the corresponding messages of CCII Recommendation T, 45 Luia 3. [In this,
Items marked with a circle are Correia 3 shown in the OSI model.
・It is a primitive between 4. O5 [In the model, the YS function targets packet-switched communication, but I
In SDN, various communication functions such as circuit switching type and packet switching type are provided, so the primitives used in the O5I model alone are insufficient for using the communication functions of ISDN. Therefore, in the present invention, brimizoib, which is necessary, is newly defined.

FIG. 4 of Table 1 is an application example of the present invention, and is a diagram showing a procedure for communication between personal computers having a disk file system.

In the same figure, adapter port 2 is a device that realizes the connection control method of the present invention, and the communication management section and the processing sections of layers 1 to 3 in FIG. 1 are each packaged. These adapters L'' and L'' are connected to two sets of para-cookers with disk file systems via interfaces A set 3.4.4 and B 4.5 and 4.6.

This application example describes file data transfer between personal computers using a line-switched communication function via a B channel with a basic access configuration provided by an adapter. In the I SDN basic access configuration,
Two B channels (circuit-switched, packet-switched +W)
64 Mbps communication path used for data transfer) and one D
A channel (a +6 Kbps communication path used for communication control information and packet-switched information transfer) is provided.

Note that Layer 3 messages sent and received between the adapter and the exchange are processed as specified in CCITT Recommendation 1.441 by the Layer Processing Is, and sent and received via the Layer 11A management section, or as shown in this drawing. For a simple explanation,
Represents messages as being sent and received between the ReaCo processing units.

Personal computer A4.7 sends a connection request primitive 4.7 via interface A4.3 to request the start of communication.
10 (CONNECT-request) is sent to the adapter port. The data communication management unit L analyzes the request and immediately requests the RIA processing unit to send a corresponding message. The Reiaco processing unit sends a message L (5ETtlP message) requesting communication monitoring.
is sent to the exchange group.

At the exchange, a B channel is set up, and a 5ETUP message 4.14 is sent to the communication center to request the start of communication.

The RAYAco processing unit 4.15 of the adapter on the destination side is S E
T [IP When a message is received, layer 3 processing is performed.

The communication management department Ridan analyzes the processing of Layer 3, confirms that the communication function is compatible, and issues a connection instruction Primidip 4.17 (1:0NNEcT-indication).
) to the personal computer 84.8 via the interface 8.

Here, an alert request primitive 4.18 (ALEI(T-r
equest), send the stiffness to the adapter port, and prepare the disk file for reception during this time. The adapter port converts the primitive 4.18 into the corresponding message 4.19 (AI, ERT message) and sends it to the exchange ().The ALERT message (also relayed by the switch ()) is sent to the originating adapter port. The originating adapter (") sends this ALERT message (") to the newly created alert instruction primitive (ALERT
-indication) and convert it to PC A4.7
to notify that it is being called. PC 84
．． In 8, when the disk file is ready, the personal computer 84.8 sends a connection response primitive 4.22 (C0NNECT-res) to respond to the request to start communication 3.
ponse) to Adabutayo Sage Rainbow 23 (CON
T message to NE) is sent to the exchange. At the exchange,
The setting of the B channel is completed, and a GONNECT message is sent to the L or the originating side, and a message Lu (CONNECT A (J message) or the destination adapter) indicating the completion of the B channel setting is sent to the destination adapter.

The terminating adapter indicates the completion of the B channel configuration using the completion instruction primitive 4.26 (READY-indica).
t, 1on) to notify the personal computer 84.8. After receiving the READY-indication primitive 4.26, the personal computer 8 waits to receive file data via the layer 3, 2 non-passing interface 84.6, which is one of the features of the present invention. When the C0NNE(:T message 4.24 reaches the originating adapter port, the adapter port sends a connection confirmation primitive 4.27 (1:O
NNECT-confirm) is sent to PC A to notify that the communication start request has been confirmed. After receiving the C0NNE(:T-confirm primitive 4.27), the PC A port starts sending the file data via the interface 84.5.

When the file data has been sent, the PC A4.7
In order to request termination processing of the connection Δ, the disconnection request primitive 4.28 (DIS(:0NNECT-raqu
esL) to the adapter port via interface A4.3. ``Adapter port'' requests disconnection of the B channel for this primitive seal, and sends message 4.
29 (DISC:0NNEC:T message) is sent to the exchange.

In the 1984 version of the international standard protocol for ISDN, when terminating communication, after disconnecting the B channel, (
Broadly speaking, there are two methods: a) sending and receiving messages between the exchange and the terminal via the D channel and then terminating the communication; and (b) terminating the communication at the same time as disconnecting the B channel. The regulation stipulates that the selection of this method should be made independently on the originating and terminating sides, by the exchange or terminal that received the DISCONNECT message. In the example shown in FIG. 4, the originating side uses method (a), and the destination side uses method (b).

At the exchange, the B channel is disconnected when the message "DISC:0NNECT L" is received, and message 4.30 (DETACil message) indicating that messages continue to be sent and received via the D channel is sent to the originating adapter ("). At the same time, T is sent to DISCONNE.
The message is sent to the destination adapter port.

When the B channel is disconnected, the destination adapter L uses the disconnection instruction primitive 4.32 (DISCONNE).
By CT-indication>, B4.
8 will be notified. The personal computer 84.8 sends a release request primitive 4.33 (RE
LEASE-request) to notify the "Application group". The adapter port sends the message L (RELEASE message) corresponding to 4.33 to the exchange ('', and the exchange terminates the communication (I (
Send ELEASE (:OMPLETE message).

"The originating adapter" sends a message to DET8C at 4.30.
Detach indication primitive 4.35 (DET
(l-indication) to PC A4.7. The computer uses the detach response primitive (DETACH-rcspo
nse) 4.36. This result is sent to the switch as a corresponding DεTAI:11 ACK message 4.37. After this, the message Lu is sent and received. To terminate communication on the originating side, switch L
” sends RELEASE message 4.39.

The originating adapter converts this 4.39 into a release instruction primitive 4.40, sends it to the personal computer A4.7, and notifies the end of communication.

Here, an example will be described in which the personal computer C5,l cannot support the requested communication function. FIG. 5 is a diagram showing the flow of signals when the requested communication function cannot be supported. In the figure, a personal computer "C" which does not have a disk file system is connected to an ataputayo which is composed of a communication management section, layer 3, layer 2, and layer 1 all together. Due to its system configuration, the personal computer C5,1 can perform message communication, but cannot transfer data between files. Therefore, if there is a request for communication for data transfer between files, it is necessary to reject this request. Therefore, using the status notification request primitive (5TATE-request),
Communication functions that can be supported in advance (in the example shown in Figure 5,
Message communications 5 and 4) are registered in the communication management section 2 of the adapter, and requests for communications other than the registered communication functions are rejected. In the example shown in FIG. 5, the first communication start request date is rejected because the request is for data transfer between files, and no notification is sent to PC C. Regarding the request to start the next communication, since a message communication has been requested, the personal computer C5,l is notified of the request to start communication, and the procedure for setting up communication is continued.

In other words, in the present invention, the information of the start request sent from the calling side terminal is analyzed, and a comparison is made to see if the called side terminal is capable of supporting the requested communication function.If it is, the called side terminal is Notify that there is a request to start communication,
It performs processing to set up a communication path, and if it is not available, it notifies the originating terminal of information to deny the communication function.

In addition, in the above explanation, the terminal with the Layer 4 function was explained as an example, and the Layer 4 function is not limited to the description.
It can be applied to all terminals with 7 functions. Also, O5
It can also be applied to terminals with configurations that do not conform to the I model.

(Effects of the Invention) As described above, the present invention provides a communication management unit between a terminal and Layer 3 for converting information between Layer 3 and Layer 4 or higher, and provides two information transfer paths. By setting and using different information depending on the content of the information, ISDN communication functions can be used with a common interface that is not limited to the type of terminal function or communication function. Furthermore, by registering the communication functions of the terminal in advance, which is the second feature of the present invention, it is possible to improve the communication efficiency, and the effect is extremely large. In addition, by independently implementing the communication connection control method of the present invention as an adapter, almost no additional information is added to terminals such as personal computers that have only simple communication procedures (IS
It becomes possible to provide DN communication functions, and an advanced communication service that combines terminal functions and ISDN communication functions can be realized.

[Brief explanation of the drawing]

FIG. 1 is a first embodiment of the present invention, and is a diagram for showing the system configuration of the communication connection control method, and FIG. 2 is a diagram for explaining the flow of signals using the communication connection control method according to the present invention. FIG. 3 is a second embodiment of the present invention and is a diagram for explaining a method of selecting compatible communication functions.
FIG. 4 is a diagram for explaining the flow of signals when the communication connection control method according to the present invention is used for file data transfer between personal computers, and FIG. 5 is a diagram for explaining the flow of signals when the communication function according to the present invention is different. FIG. 2 is a diagram for explaining the flow.

Claims (2)

[Claims] (1) I configured between terminals with layer 4 or higher functions via an exchange with ISDN international standard protocol
A layer 3, layer 2, and layer 1 processing unit is sequentially arranged between the terminal and the communication path of the ISDN, and when a communication request is made, the communication between the terminals on the calling side and the called side is In the communication connection control method that connects and communicates,
A communication management unit is provided on the layer 3 side and has a function of converting into an information signal between the terminal and the layer 3, and a first information transfer path is provided between the communication management unit and the terminal. , after providing a second information transfer path between the layer 1 and the terminal without passing through the layer 3 and the layer 2, and notifying both the terminals of the completion of the setting when the communication path setting is completed, An ISDN communication connection control system, characterized in that the first or second information transfer path is selectively used depending on the content of signals sent and received by the terminal. (2) I configured between terminals with functions of layer 4 or higher via an exchange having ISDN international standard protocol
A layer 3, layer 2, and layer 1 processing unit is sequentially arranged between the terminal and the communication path of the ISDN, and when a communication request is made, the communication between the terminals on the calling side and the called side is In the communication connection control method that connects and communicates,
A communication management unit is provided on the layer 3 side and has a function of converting into an information signal between the terminal and the layer 3, and the types of communication functions that each of the terminals can support are registered in advance in the communication management unit. When the communication management unit receives a communication start request control signal from the calling terminal via the exchange, the content of the control signal is analyzed and the pre-registered information on the called terminal is determined. If the communication functions match, processing is performed to notify the receiving terminal of the arrival of the communication start request and set up a communication path, and if the content of the control signal does not match, the communication is terminated. 1. An ISDN communication connection control system, characterized in that a signal rejecting connection setup is transmitted to the originating terminal.