JPH0662082A - Isdn terminal equipment - Google Patents

Abstract

PURPOSE:To evade a communication infeasible state by automatically setting a new TEI value by ISDN terminal equipment even when a condition to release a TEI value occurs in the ISDN terminal equipment using non-automatic TEI allocation as for the ISDN terminal equipment. CONSTITUTION:When a communication control part 6 detects the occurrence of a prescribed release condition for the TEI value, the TEI value in current use is released, and procedure to set the new TEI value is started up. As the TEI value to be set newly. the value in which a specific constant is added on or subtracted from a released TEI value, or a random value within a range used in the nonautomatic TEI allocation is set can be used. This device is comprised in such a way that the fact that the TEI value is set again is displayed on an LCD in an operation port part 5 for a user, or it is notified by outputting a report from an output part(plotter) 4, etc., after the new TEI value is set.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to ISDN terminals, and more particularly to ISDN terminals using non-automatic TEI allocation.

[0002]

2. Description of the Related Art Conventionally, integrated service digital network (ISD)
N: Integrated Services Digital Network) ISDN terminal devices that are connected to each other and perform digital communication with each other are widely used. Various signals are exchanged between the ISDN user and the network in order to set or release communication, and is defined as a user-network protocol. This ISDN user-network protocol is OSI
(Open System Interconnection) Layers are divided into layers 1 to 3 based on the reference model. Above all, layer 2
Is commonly known as D channel link access procedure (LAP
D: Link Access Procedure on the D-channel), which has a function of overcoming a transmission error or the like in a frame unit of information between a user and a network to perform highly reliable signal transfer.

In the basic interface, in order to ensure portability that a certain terminal equipment (TE) can be used anywhere, each terminal equipment has a terminal termination point identifier (T).
An EI (Terminal Endpoint Identifier) is assigned. In other words, this TEI value is not registered in the network in advance, but the TEI value is assigned according to a predetermined procedure when necessary.

This TEI value allocation includes automatic TEI allocation and non-automatic TEI allocation, and the TEI value of automatic TEI allocation given by the network based on a request from a terminal device is 64 to 12.
The TEI value of the non-automatic TEI allocation is assigned in the range of 0 to 63. And non-automatic TEI
The allocation is used when the terminal is set in advance by the DIP switch or the ROM, and unlike the case of the automatic TEI allocation, the TEI allocation request from the terminal device to the network is not made.

As described above, in the conventional ISDN terminal device that performs non-automatic TEI allocation, the user is solely responsible for the TEI value used, and the terminal device is responsible for the TEI.
The processing when detecting multiple allocation of values or after the network releases the TEI value has merely stopped by notifying the user that the TEI value has been released.

[0006]

As described above, in the conventional ISDN terminal device, the processing when the TEI value is released is merely to notify the user that the TEI value has been released. If a condition for canceling the TEI value occurs, there is a problem that the calling / calling operation cannot be performed until the user sets a new TEI value.

The present invention has been made in view of the above-mentioned conventional problems, and in an ISDN terminal using non-automatic TEI allocation, even if a condition for canceling the TEI value occurs, IS
It is an object of the present invention to provide an ISDN terminal device in which a DN terminal can automatically set a new TEI value and avoid a communication incapable state.

[0008]

The invention according to claim 1 is
It has an interface means connectable to ISDN, and C
Q. of CITT Recommendation In the ISDN terminal device performing the LAPD procedure according to 921 and performing the non-automatic TEI allocation, the TEI value multiple allocation detecting means for detecting the multiple allocation of the TEI value and the multiple allocation of the TEI value when the non-automatic TEI allocation is used. When detected, it is characterized by comprising TEI value canceling means for canceling the TEI value being used and TEI value setting means for automatically setting a new TEI value.

The invention according to claim 2 has an interface means connectable to the ISDN, and the Q. In the ISDN terminal device performing the LAPD procedure according to 921 and performing the non-automatic TEI allocation, the TEI value cancellation condition detecting means for detecting the occurrence of the TEI value cancellation condition from the network, and the non-automatic TEI allocation use. When the condition for releasing the TEI value from the network is detected, the TEI value releasing means for releasing the TEI value in use and a new TEI value are released.
And a TEI value setting means for automatically setting a value.

The invention according to claim 3 is the invention according to claim 1 or 2.
The described ISDN terminal device is characterized in that the TEI value newly set automatically is set to a random value within a specified range. According to the invention of claim 4, in the ISDN terminal device of claim 1 or 2, the TEI value that is newly automatically set is released so that it is adjacent to the TEI value that is released within the specified range.
It is characterized in that a value obtained by adding or subtracting a predetermined constant amount to the value is set as the TEI value.

According to a fifth aspect of the present invention, in the ISDN terminal device according to the first to fourth aspects, a display means for displaying a predetermined message to a user is provided, and when the non-automatic TEI allocation is used, the TEI value is released and the TEI value is automatically set. It is characterized in that the fact that a new TEI value is set is displayed to notify the user.

[0012]

In the invention according to claim 1 or 2, the non-automatic TE
In an ISDN terminal device that performs I allocation, even if the TEI is released, the ISDN terminal automatically creates a new TEI.
Since the setting is made, it is possible to avoid the communication-disabled state due to the cancellation of the TEI.

In the third aspect of the present invention, since a random number (random value) is used as the TEI value newly automatically set, it is possible to reduce the possibility of multiple allocation of TEI values. In the invention according to claim 4, since the adjacent values before and after the released TEI value are used as the TEI values that are newly automatically set, the TEI values are assigned and managed within a specific range for each ISDN terminal. T in such a situation
It is possible to reduce the possibility of multiple allocation of EI values.

According to the fifth aspect of the invention, the TEI can be easily managed by the user by displaying on the display means that the new TEI value has been set and notifying the user.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. First, the configuration will be described. FIG. 1 shows an I according to an embodiment of the present invention.
It is a block diagram which shows the structure of an SDN terminal device.

In the figure, 1 is a system control unit (SC
U: System Control Unit) controls the entire ISDN terminal device. A storage unit 2 stores transmission / reception data, parameters relating to system control, and the like. An input unit 3 is a scanner or the like that reads transmission originals and creates transmission data.

An output unit 4 is a plotter or the like for recording and outputting the received data on recording paper or the like. Reference numeral 5 denotes an operation port unit, which is a keyboard for operating the system control by the user and L for notifying the user of a predetermined message.
It is equipped with a display such as a CD.

Reference numeral 6 is a communication control unit (CCU: Communication)
Control Unit) controls communication between ISDN terminals via ISDN (Integrated Services Digital Network). 7 is a line terminating device (DSU: Digital Service Uni)
At t), the digital signal transmitted / received by the terminal device and the digital signal suitable for the transmission path are converted. A bus 8 is connected to the respective parts of the ISDN terminal device and is mutually accessible.

FIG. 2 is a diagram showing the configuration of the communication control unit according to an embodiment of the present invention. In the figure, the communication control unit (CC
U) 6 has a D-ch call control unit 9 and a B-ch control unit 10, and the D-ch call control unit 9 is an ISDN D-
It provides a physical / electrical interface for connecting to ch call control (Layer 1 to Layer 3) and ISDN. The B-ch control unit 10 controls ISDN B-ch communication.

FIG. 3 is a diagram showing an example of the structure of the LAPD frame of the D channel layer 2. In the figure, each frame is defined in units of octets (8 bits), and although not shown, the service access point identifier (SA
Before PI), there is a start flag indicating the start of the frame. Next is an address field for identifying the logical link, and a control field indicating what kind of frame this is, followed by an information field not shown in the case of an information frame. Then, after that, a frame check sequence (FCS: Frame Check Sequence) for detecting a reception error such as a transmission line error.
ce) is followed by an end flag (not shown) indicating the end of the frame.

The transmission order of the bits on the D channel of this LAPD frame is as follows: bit 1 (b1), bit 2 (b2), ... Of octet 1 shown in FIG. 3, and finally octet n (final octet). 8) is sent. The address field is composed of 2 octets. Bit 1 of the first octet is an extension bit (EA), and command / response bit (CR) of bit 2 is, for example, a non-auto TEI assigned synchronous extended balanced mode setting (SABME: Set Asynchronous Balanced).
Mode Extended) A command that requests a specific operation for the receiving side of a frame, such as a request to set a logical link by a frame, or an unnumbered confirmation (UA: Unnumbered A)
cknow-ledge) Indicates a response that reports the operation or status executed, such as confirmation of logical link setup by a frame. Further, in bits 3 to 8 of the first octet, SAPI indicating the type of service receiving port provided by layer 2 is configured. Furthermore, bits 2 to 8 of the second octet form a TEI for identifying the terminal device.

The TEI allocation procedure includes automatic TE
There are I allocation and non-automatic TEI allocation, and the TEI value of automatic TEI allocation of 64 to 126 and the TEI value of non-automatic TEI allocation of 0 to 63 can be used. Therefore, in the conventional ISDN terminal device, the automatic TEI allocation procedure is normally used, and when TEI is released, I
The D acquisition procedure is activated and communication is performed using the TEI value given from the network. Thus, all TEIs were managed by the network.

However, when the non-automatic TEI allocation procedure is used in the conventional ISDN terminal device, the user is responsible for managing the TEI value, and when the TEI is released by the ISDN terminal, the TEI value is notified to the user. ISD until the user sets a new TEI value.
N terminal cannot activate D channel layer 2,
It was impossible to send and receive.

Next, the operation will be described. The network is the TEI that is actually used by the terminal device connected to the interface.
It is regularly checked whether or not multiple allocation of values or TEI values has occurred. Specifically, the network sends a TEI value check request message to each terminal side. At this time, the action indicator (Ai: Action Indicator) and the reference number (Ri: Reference Number) are Ai = 127, R.
Let i = 0. Upon receiving this, each terminal device puts the TEI value used by itself in Ai and the random number generated by each terminal device in Ri, and sends it to the network as a check response message. Here, the reason why each terminal device puts a random number in Ri is to facilitate detection of multiple allocation in which a plurality of terminal devices use the same TEI value. When the network receives the check response message from all the terminal devices, the TEI management information is updated based on this. In this way, TEI
Multiple assignments of values can be detected.

Therefore, in the embodiment according to the invention described in claim 1, when non-automatic TEI allocation is used and the above multiple allocation of the TEI value is detected, the TEI value in use is released and a new TEI value is released. The value is set automatically. For this reason, conventionally, only the user is notified of the cancellation of the TEI value, but in the case of the present embodiment, since a new TEI value is set immediately, the state without the TEI value does not continue, and TE
It is possible to avoid the communication-disabled state caused by canceling the I value.

Next, FIG. 4 is a flow chart for explaining the operation of the ISDN terminal device according to the invention described in claims 2 to 5. As shown in FIG. 4, in step 100, TE
The occurrence of the I release condition is detected. As the TEI cancellation conditions, here, when an ID cancellation message is received from the network, when an unsolicited UA response frame is received, the SABME command is retransmitted n200 times, and the DISC (Disconnect) command is n20.
There are 0 retransmission errors. When the occurrence of any of the above cancellation conditions is detected, the TEI value in use is canceled (step 101) and a new T
Start the procedure for automatically setting the EI value (step 1
02).

As shown in the flow of step 102 in FIG. 4, as the TEI value to be newly set, 1) the released TE
Add any suitable constant "X" to the I value, or vice versa.
2) Any appropriate constant "X" is subtracted from the released TEI value, or 3) a random number generation system is used to set a random value within the range used for non-automatic TEI allocation. Is.

As described above, when adjacent values before and after the released TEI value are set as new TEI values, IS
In a situation where TEI values are assigned and managed within a specific range for each DN terminal, the possibility of multiple assignment of TEI values can be reduced (example of claim 4), and new automatic setting is possible. Even when a random value is used as the TEI value to be set, the possibility of multiple allocation of the TEI value can be reduced (the embodiment according to claim 3).

In this way, when the new TEI value is automatically reset after the TEI value being used is released, the user is notified of that fact (step 103). As means for notifying the user, as shown in the flow of step 103 in FIG. 4, 1) displaying on the LCD, 2) outputting as a report from the plotter, 3) other means such as voice. It can also be notified by a buzzer or the like. This allows the user to easily manage the TEI.

[0030]

According to the invention of claim 1 or 2,
Even if the TEI is released in the ISDN terminal device that performs non-automatic TEI allocation, the ISDN terminal automatically sets a new TEI, so that the communication-disabled state due to the release of the TEI can be avoided. According to the invention as set forth in claim 3, since a random number is used for the TEI value newly automatically set, it is possible to reduce the possibility of multiple allocation of the TEI value.

According to the invention as set forth in claim 4, since the adjacent values before and after the TEI value are used as the TEI values to be newly automatically set, the TE within a specific range for each ISDN terminal.
T under the situation where I value is assigned and managed
The possibility of multiple allocation of EI values can be reduced.
According to the invention of claim 5, the fact that the new TEI value is set is displayed on the display means to notify the user, so that the user can easily manage the TEI.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an ISDN terminal device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a communication control unit according to an embodiment of the present invention.

[Fig. 3] Fig. 3 is a diagram illustrating a configuration example of an LAPD frame of a D channel layer 2.

FIG. 4 is a flowchart for explaining the operation of the ISDN terminal device according to the invention described in claims 2 to 5.

[Explanation of symbols]

 1 system control unit 2 storage unit 3 input unit 4 output unit 5 operation port unit 6 communication control unit (CCU) 7 line terminating device (DSU)

Claims (5)

[Claims] 1. Q.I. of CCITT recommendation having interface means connectable to ISDN. LAP according to 921
ISDN that performs non-automatic TEI allocation along with D procedure
In the terminal device, TEI value multiple allocation detecting means for detecting multiple allocation of TEI value, and TEI value releasing means for canceling TEI value in use when multiple allocation of TEI value is detected when the non-automatic TEI allocation is used. And a TEI value setting means for automatically setting a new TEI value. 2. A Q.T. of CCITT recommendation having interface means connectable to ISDN. LAP according to 921
ISDN that performs non-automatic TEI allocation along with D procedure
In the terminal device, a TEI value cancellation condition detecting means for detecting that a condition for canceling the TEI value from the network has occurred, and when the condition for canceling the TEI value from the network is detected when the non-automatic TEI allocation is used, it is in use. Release TEI value of T
An ISDN terminal device comprising: an EI value canceling means; and a TEI value setting means for automatically setting a new TEI value. 3. The ISDN terminal device according to claim 1 or 2, characterized in that the TEI value newly set automatically is set to a random value within a specified range. apparatus. 4. The ISDN terminal device according to claim 1, wherein the TEI value newly set automatically is adjacent to the released TEI value within the specified range, with respect to the released TEI value. An ISDN terminal device, wherein a value obtained by adding or subtracting a predetermined constant amount is set as a TEI value. 5. The ISDN terminal device according to claim 1, further comprising display means for displaying a predetermined message to a user, wherein the TEI value is released when the non-automatic TEI allocation is used and a new TEI value is automatically set. An ISDN terminal device, characterized in that the user is notified of the fact that the setting has been made.