JPH02159861A - Transmission control method for isdn terminal equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transmission control method for an ISDN terminal device that uses ISDN as a transmission path.

[Prior Art] Generally, when data is transmitted using ISDN, charges are normally charged to the calling terminal. Furthermore, when a call is made to a terminal that has a contract to receive a so-called collect call service from the ISDN, charges are charged to the called terminal rather than to the calling terminal.

[Problems to be Solved by the Invention] In this way, conventionally, unless a collect call service contract is made with ISDN, charges are charged to the calling terminal. This was inconvenient when the operator of the calling terminal did not have sufficient funds available or when the cost of communication with a foreign country varied depending on the direction of the call.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a transmission control method for an ISDN terminal device in which one charging terminal can be freely set.

[Means for Solving the Problems] In the present invention, a call solicitation mode is introduced, the terminal that made the call in such mode once recovers the call, and then the terminal that made the call in the call solicitation mode makes the call. When a call is made, charges are charged to the own terminal.

[Function] Therefore, it is possible to arbitrarily set the terminals to be charged for one communication, thereby improving the usability of the ISDN terminal device.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an ISDN telephone according to one embodiment of the present invention.

In the figure, a CPU (central processing unit) 1 is connected to this IS.
It executes control processing for the entire DNf1 phone, and R
The OM (read-only memory) 2 stores the control processing program executed by this CPUI and various data necessary for the control processing program.
M (random access memory) 3 is this ISDN
It is used to store various types of information unique to the telephone, such as answering machine management information that stores the answering machine setting status of sub-addresses, and the like.

The operation display section 4 is used to operate this ISDN telephone, and consists of various operation keys and a display.The tone generation circuit 5 generates a ring tone to call the operator when an incoming call is detected, and a warning tone to alert the operator. The speaker 6 is for generating various tone signals such as a beep sound to arouse the sound, and the speaker 6 is for outputting the various tone signals generated from the tone generating circuit 5.

The ISDN interface circuit 7 is for connecting this ISDN telephone to the ISDN network terminal (NT), and the LAPD control unit 8 is for realizing line control processing of the ISDN basic interface function. The audio signal converter (CODEC) 9 is for converting an analog audio signal for one call into a digital signal that can be handled by rsDN and transmitting it, and the handset 10 is for making a call. The hook switch 11 is for detecting the hook state of the handset 10, and its detection signal is output to the CPUI.

The audio encoding/synthesizing device 12 encodes the analog audio signal into audio data and synthesizes the original analog audio signal based on the audio data, and the audio memory device 13 encodes the analog audio signal into audio data. It is for storing the formed voice data, voice data of a guidance message (described later) in response to the other party's terminal device, and data of a beep sound which is a tone signal of a constant frequency.

The analog audio signal output from the audio signal converter 9 is
One switching connection end 14b of this switch 14 is connected to the common connection end 14c of the switch 14.
The other switching connection end 14a of the switch 14 is connected to the analog audio signal input end of the audio encoding/synthesizing device j[12.

The analog audio signal output from the audio encoding/synthesizing device [12 is applied to the other switching connection end 15a of the switching device 15 and one switching connection end 16a of the switching device 15,
The common connection end 15c of the switch 15 is connected to the input connection end of the speaker 10a of the handset IO.

The output signal from the microphone 10b of the handset 10 is applied to the other switching connection end 16b of the switch 16, and the common connection end 16c of the switch 16 is connected to the analog audio signal input end of the audio signal converter 9. has been done.

In addition, the CPU 1, ROM 2, RAM 3, operation display section 4,
Tone generation circuit 5, ISDN interface circuit 7, L
The APD control section 8, the audio signal conversion section 9, and the audio encoding/synthesizing device ff112 are connected to a system bus 17, and various information exchanged between these elements is via this system bus 17. It is done.

Further, the operation of the switching devices 14, 15, and 15 is controlled by the CPU.

FIG. 2 shows an example of the operation display section 4 of this ISDN telephone.

In the figure, the numeric keypad 4a is used to indicate the destination telephone number (Engineering SD).
This is for entering numerical information such as N number).
The set key 4b is used to specify the timing for confirming input information from the numeric keypad 4a and importing it into the ISDN telephone, and the clear key 40 is used to erase input information input from the numeric keypad. The at-home key 4d is used to set the mode of this SDN telephone to either the away mode or the at-home mode, and the call solicitation reception key 4e is used to accept or accept incoming calls in the call solicitation mode. The response destination registration key 4f is used to input the call solicitation reception mode, and the response destination registration key 4f is used to register the terminal to which the call solicitation mode is to be accepted.The call solicitation key 4g is used to input the call solicitation mode. This is for inputting the operation to make a call in mode.

The lamp 4h indicates that this ISDN telephone is set to the away mode, and the lamp 41 indicates that
This is to display that the call solicitation reception mode is set, and the liquid crystal display 4j is used to display and output various guidance information from this ISDN telephone to the operator, numerical information inputted from the numeric keypad 4a, etc. belongs to. In this embodiment, the set key 4b and clear key 40 are used as keys for responding to guidance messages.

Furthermore, a monitor speaker 6 is built in under the transfer reset key 4f, and a handset 10 is installed on the left side of the housing.
There is a space available to accommodate.

A hook switch 11 is disposed at a position where the hook state of the handset 10 can be detected.

In this way, the operating mode of this ISDN telephone is
It has four operating modes, which are a combination of an absentee mode or at-home mode, and a call solicitation acceptance mode or a non-call solicitation acceptance mode.

In order to store such operation modes, the RAM 3 stores terminal status information STA as shown in FIG. 5(a).

This terminal status information STA includes a call solicitation acceptance mode flag FCA for storing that the call solicitation acceptance mode is set, an absent mode flag FNA for storing that the absent mode is set, and , an answering machine flag FRD that indicates that a message from the other party is being recorded using the answering machine function.

Furthermore, as shown in FIG. 3(b), the RAM 3 stores a response destination table TBR in which the ISDN number of the terminal to which the 5-call solicitation mode is to be accepted is registered.

For example, when the away home key 4d is turned on and the away mode flag FNA is reset and the home mode is set, the CPU
to set the away mode, and turn on lamp 4.
Start lighting h.

Further, when the away home key 4d is turned on and the away mode flag FNA is set and the away mode is set, the CPU 1 resets the away mode flag FNA to set the home mode, and also resets the away mode flag FNA and sets the home mode. 4 hours
Turn off the light.

Furthermore, at this time, the answering machine flag FRD is checked, and if the answering machine flag FRD is set, a beep sound generated by the tone generating circuit 5 is output from the monitor speaker 6 to draw the operator's attention, and the LCD screen On the display 4j,
For example, the guidance message ``There is a voice mail message.If you wish to hear it, please pick up the handset and turn on the set key.j'' will be displayed.Then, when the handset 10 goes off-hook and the set key 4d is turned on. When this is confirmed, the switch 15 is switched to the switching connection end 15a side to cause the voice encoding/synthesizing device 12 to reproduce the stored message and output it to the speaker 10a of the handset 10.

Further, when the call solicitation reception key 4e is turned on and the call solicitation reception mode flag FCA is reset, the CPUI sets the call solicitation reception mode flag FCA and starts lighting the lamp 41. do.

When the call solicitation reception key 4e is turned on and the call solicitation reception mode flag FCA is set, the C
The PUI resets the 1-call solicitation reception mode flag FCA and turns off the lamp 41.

In this way, the away mode and at-home mode are set and set, and the call solicitation reception mode is set/cancelled. When the away mode is set, the lamp 4h lights up, and the call solicitation reception mode is set. lamp 41 when
lights up.

Also, when the response destination registration key 4g is turned on, the CPU
Performs a predetermined response destination registration interaction process.

ISD of the other party's terminal that accepts and accepts one call solicitation from the operator
Have the operator input the N number.

Here, the basic transmission procedure performed by the ISDN telephone during a call will be explained.

As shown in FIG. 4(a), the originating terminal first sends a call setup message 5ETUP to the ISDN to request call setup with the destination terminal, and the ISDN sends a call setup message 5ETUP to the specified destination terminal. Send and make a call.

Upon receiving the call setup message 5ETUP, the ISDN:
Call setup acceptance message CA to notify call setup status
Sends LL-PROC to the originating terminal.

When the destination terminal detects an incoming call, it starts ringing to call the operator of its own terminal and sends a paging message ALERT to the ISDN, and the SDN sends a paging message ALERT to the originating terminal to call the terminating terminal. Notify that it has started. In addition, the calling message ALER
T is repeatedly output at an appropriate period.

When the operator who hears the ring tone picks up the handset 10 and detects that it has gone off-hook, the called terminal stops outputting the calling message ALERT and sends a response message C0NN to the ISDN, and the ISDN sends the response message C0NN to the originating terminal. to notify that the called terminal has accepted the call.

In addition, ISDN sends a response confirmation message C0N to the destination terminal.
A NACK is sent to confirm the response of the destination terminal, at which point an information channel for data transmission is established between the originating terminal and the destination terminal.

As a result, the calling terminal and the receiving terminal are in a state where they can talk to each other, and the calls are made between the respective operators.

Then, when the call ends and the operator on the originating terminal goes on-hook first, the originating terminal sends a disconnection message DISC to the ISDN to request release of the information channel, and the ISDN
The DN sends a disconnection message DISC to the destination terminal to notify that the information channel has been restored.

As a result, when the destination terminal responds to ISDN with a release message REL notifying that the channel has been disconnected, the ISDN sends a release message REL to the originating terminal.0 When the channel release is completed, the originating terminal sends a release message REL to the ISDN.
L-COMP is sent to the ISDN to notify the ISDN, and the ISDN then sends a release completion message REL-CO.
The information channel is released by sending the MP to the destination terminal, and the information channel set between the originating terminal and the destination terminal is completely released.

In this way, an information channel is set up between the originating terminal and the terminating terminal, a call is made between the operators, and the information channel is released.

Furthermore, after one call ends, the operator of the terminating terminal can go off-hook first and open the information channel. In that case, the terminating terminal sends a disconnection message DISC, as shown in Figure (b). Release of the information channel is requested.

Next, 5 call setup messages 5 ETUP and release completion messages R necessary to realize the transfer function of this embodiment.
The contents of EL-COMP will be explained.

First, each message includes a protocol identifier for identifying the protocol specifications (format, sequence, etc.) that define the layer 3 call control message, as shown in Figure 5(a), and a protocol identifier for identifying the protocol specification (format, sequence, etc.) that defines the layer 3 call control message, and a message indicating which call the message is related to. A call number to identify the message, a message type to identify the content of each message, a mandatory information element that is always added to each message, and an information element that is added to each message as necessary. Consists of additional information elements. Note that the required information elements are 0, 1, etc. depending on the message type. Alternatively, a plurality of additional information elements are set, and zero, one, or a plurality of additional information elements are arranged depending on the situation.

Call setting message SF! As shown in Figure (b), TUP has "transmission ability" as an essential information element, and additional information elements as "terminal function", "calling number", "r called number",
It also has information elements such as "user/user".

The release completion message REL-COMP has a "reason indication" as an essential information element, as shown in (e) of the same figure,
It has "display" and "user/user" as additional information elements.

Here, an outline of each information element will be explained.

The "transmission capability" information element indicates whether the content of the information to be transmitted is voice, unrestricted digital information, restricted digital information, or 3.1KI.
(Information transfer capability indicating whether it is z audio, 7Hz audio, or video, transfer mode indicating whether the switching function used is circuit switching or packet switching, and information transfer speed) It consists of information that describes the information transfer rate, information transfer format, and user information protocol.

The "terminal capabilities" information element is used to indicate to the network the capabilities of a stem mode terminal, such as a telephone.

The "calling number" information element indicates the ISDN address (number) of the calling terminal, and the "terminating number" information element contains the ISDN address (number) of the calling terminal.
Hail DN address.

The "reason display" information element is used to describe the reason for the generation of a certain message, to provide diagnostic information in the case of a procedural error, and to indicate the source of the reason.

The "display" information element is used to display various display information transmitted from the network to the terminal, such as usage charges, on the terminal.

The "user-to-user" information element is used to transmit information between users, and the contents of this information element are transparently transmitted to the other party's terminal without being interpreted by the network.

With the above configuration, a telephone TEa having the same configuration as in FIG.
However, a case will be described in which a telephone TEb having the same configuration as that in FIG. 1 is used to make a call in the call solicitation mode.

Without picking up the handset 10, the operator of the telephone TEa turns on the call solicitation key 4g to set the call solicitation mode, and presses the I of the telephone TEb from the numeric keypad 4a.
When you input the SDN number, turn on the set key 4b, and input the command to start making a call, the telephone TEa
A call setting message 5ETUP with "r call invitation mode" set as the content of the "user" information element is sent to the ISDN (see FIG. 6).

Therefore, a call setting message 5ETUP having the same "user-user" information element is outputted from the ISDN to the telephone set TEb.

When the telephone set TEb receives the call setting message 5ETUP, it checks the contents of the "user-user" information element, and at this time, since "r call solicitation mode" is set,
Call solicitation acceptance mode flag FCA of terminal status information STA
, the contents of the absent mode flag FNA are checked, and it is also checked whether the same ISDN number as the contents of the "calling number" information element of the call setting message 5ETUP is registered in the response destination table TBH.

Then, the telephone TEb has 1 call solicitation reception mode flag F.
When CA is set, the absent mode flag FNA is reset, and the ISDN number that is the same as the content of the "calling number" information element is registered in the response destination table TBH (hereinafter referred to as case ■), It responds with a release completion message REL-COMP in which data indicating "at home, call solicitation available" is set in the "user/user" information element.

In addition, the call solicitation reception mode flag FCA is set,
And, the away mode flag FNA is set, and “
If the same ISDN number as the content of the "Calling number" information element is registered in the response destination table TBR (hereinafter, case
), it responds with a release completion message REL-COMP in which the "user-user" information element is set with data indicating "not at home, call solicitation available."

If the call solicitation reception mode flag FCA is set, but the ISDN number that is the same as the content of the "calling number" information element is not registered in the response destination table TBH (hereinafter referred to as
In the case (referred to as (3)), a release completion message REL-COMP is responded with data indicating that "call invitation not possible" set in the "user-user" information element.

If the call solicitation reception mode flag FCA is not set (hereinafter referred to as case ■), respond with a release completion message REL-COMP in which data related to call solicitation reception is not set in the "user ° user" information element. .

If one communication is in progress (hereinafter referred to as case 2), a release completion message REI, GOMP with data indicating "in communication" set in the "user-user" information element is responded.

Release completion message RE! The telephone TEa that has received the L-COMP displays the following guidance messages on the liquid crystal display 4j in accordance with the contents of the "user-user" information element, and performs call recovery.

That is, in case ■, the release completion message RE! L-C0
When you receive an MP message, for example, ``I'm at home.

``I will call you shortly.'' is displayed.

When the release completion messages REI and COMP in case (2) are received, for example, a guidance message such as "I'm away. I'll be in answering mode soon." is displayed.

When the release completion message REL-COMP in case (2) is received, for example, a guidance message such as "Call invitations cannot be accepted. Please call again in normal mode." is displayed.

When you receive the release completion message REL-GOMP in case ■, for example, [The phone number you called is
Call solicitation is not possible. ” is displayed.

When the release completion message REL, -COMP in case (2) is received, for example, a guidance message such as "You are currently on the phone. Please call again." is displayed.

In this way, the operator of telephone TEa can know the status of telephone TEb.

On the other hand, in case (3), the telephone TEb once recovers the call and calls the telephone TEa after, for example, 3 seconds.

This allows the phone TF! When a detects an incoming call, the phone I
The f&TEa outputs a ringing tone generated from the tone generation circuit 5 from the monitor speaker 6 to call the operator,
When the operator hears the ringing tone and picks up the handset IO and detects that the handset IO is off-hook, it stops outputting the ringing message ALERT and sends a response message C0NN to the ISDN.

This causes the telephone TEb to send a response message C0NN.
When the telephone TEb receives this, the telephone TEb outputs a ringing tone generated by the tone generating circuit 5 from the monitor speaker 6 to call the operator.

When the operator hears this ringing tone and picks up the handset 10, the operator of the telephone τEa and the telephone TEb
It is now possible to talk between operators.

In this way, the call solicitation mode set by telephone TEa is accepted by telephone TEb, the call is temporarily restored, telephone τEb makes a call to telephone TEa, and the operator of telephone Tll'a When the telephone TEb comes out, the telephone TEb emits a ring tone for the first time to call the operator, so that the operators can talk to each other.

Therefore, the charge is not paid to the operator who desires the call, but to the operator of the other party who is called by the call, so that it is possible to perform a substantial incoming call charge.

Further, in case (3), the telephone TEb calls the telephone TEa after the call is restored, and when the telephone TEa detects an incoming call, the a-filler TEa transmits the ringing tone generated from the tone generation circuit 5 to the monitor speaker 6. output and call the operator.

When the operator who hears the ring tone picks up the handset 10 and detects that it has gone off-hook, the telephone TEa stops outputting the ringing message ALERT and sends a response message C0NN to the ISDN.

As a result, the telephone TBb that has received the response message C0NN switches and connects the switch 14 to the switch connection end 14a side, switches and connects the switch 16 to the switch connection end 16a, and in this state, the voice encoding/synthesizing device 12-1 For example, an answering machine guidance message such as "I'm out now. Please speak your message after the beep." is output, and the answering machine guidance message is sent to the telephone TEa.

After the voice encoding/synthesizing device 12 synthesizes and outputs the beep sound, the recording operation of the voice encoding/synthesizing device 12 is started. After the recording operation is performed for a certain period of time, the recording operation of the voice encoding/synthesizing device I2 is stopped, and the answering machine flag FRD of the terminal status information ST^ is set, and the voice encoding/synthesizing device 12 synthesizes and outputs the beep sound again. After that, the line will be restored.

Therefore, the operator of telephone TEa
Since the message to the operator b can be recorded by answering machine and the billing at that time is made to the telephone TEb, in this case as well, it is essentially an incoming call billing.

Also, in cases ■, ■, ■, the telephone TEb is.

Do not make a call.

By the way, if the operator of the telephone TEa sets the call solicitation mode and the destination is unable to recognize the call solicitation mode, as shown in FIG. TEc performs the normal incoming call operation, sounds a ringtone on its own terminal, and sends a call message AL.
It responds with ERτ.

At this time, the telephone TEa sends an immediate disconnection message DI.
It sends SC, starts call recovery, and does not connect to telephone TEc.

FIGS. 8(a) to 8(c) show examples of processing performed by this ISDN telephone upon detecting an incoming call.

That is, upon receiving the call setup message 5ETUP,
It is checked whether the "user-user" information element includes information on the call solicitation mode (decision 101), and if it is not included (the result of determination 101 is No), then other destinations It is checked whether the communication is in progress (decision 102).

When the result of judgment 102 is YES, the call setting message 5ETUP is ignored (process 103).

When the result of judgment 102 is NO, the away mode flag FNA of the terminal status information STA is set.
, it is checked whether the absentee mode is set (decision 104), and when the result of determination 104 is No, the normal operation when receiving a call is performed.

That is, the process 105) of responding to the ISDN with a paging message ALERT and outputting a ring tone output from the tone generating circuit 5 from the monitor speaker 6 to call the operator is performed, and the operator picks up the handset 10 and goes off-hook in the process 105. Repeat until (
No loop of decision 106).

When an off-footer is detected and the result of judgment 106 is YES, a response message C0NN is sent (step 107), and the call between the operators is terminated, and the operator of the own terminal returns the handset 10 first and goes on-hook.

Alternatively, the operator at the other end can first use handset 1.
Returns 0, goes on-hook, and waits until it receives a disconnect message DISC from ISDN (decision 108゜109
No loop).

When the result of judgment wR108 is YES, perform the call recovery procedure when disconnection was initiated from the own terminal (processing 110);
In addition, when the result of judgment 109 is YES, the call recovery procedure performed when disconnection was started from the other party's terminal is performed (process 11
1).

On the other hand, if the absentee mode is set and the result of the judgment 104 is YES, a response message C0NN is sent (step 112), and when the switch 14 is switched to the switching connection end 14a side, the switch 16 is switched and connected. While switching to the end 16a, the voice mail guidance message as described above is synthesized and outputted from the voice encoding/synthesizing device 12 (
After processing 113), the beep sound is synthesized and output from the speech encoding/synthesizing device 12 (processing 114), and then the recording operation of the speech encoding/synthesizing bag ff112 is started (processing 115).

Then, it waits until a predetermined recording time has elapsed or the operator at the other end finishes inputting the message and goes on-hook, thereby sending out the disconnection message DISC (No loop at decisions 116 and 117).

When the predetermined recording time ends and the result of the judgment 116 becomes YES, the recording operation of the audio encoding/synthesizing device 12 is ended and the answering machine flag FRD is set (step 118), and the audio encoding/synthesizing device 12 outputs a message. While re-synthesizing and outputting the sound (process 119), the switch 14.1
6 is restored to its original state, and the process proceeds to step 110, where the call is restored.

Further, when the operator of the other terminal finishes inputting the message and receives the disconnection message D ISC and the result of judgment 117 becomes YES, the recording operation of the voice encoding/synthesizing device 12 is terminated and the answering machine flag FR'D is 120), the switching device 14, 16 is restored to its original state, and the process proceeds to step 111, where the call is restored.

On the other hand, if the "user-to-user" information element of the call setting message 5 ETUP includes information on the call solicitation mode and the result of judgment 101 is YES, whether or not communication is currently in progress with another destination. (Judgment 121) 1 When the result of judgment 121 is YES, in the above case ■
In this case, the release completion message R sets the data indicating "Communicating" in the "User/User" information element.
EL-COMP is responsively processed 122) and the call is restored.

When the result of judgment 121 is No, it is checked whether the call solicitation acceptance mode flag FCA of the terminal status information STA is set and the call solicitation can be accepted (judgment 123). 123 result is No
When this happens, it is the case of the above-mentioned case (■), so the release completion message REL-COMP does not have data related to call solicitation reception set in the "user-user" information element.
124), and the call is restored.

If the result of judgment 123 is YES, the "calling number"
Check whether the same ISDN number as the content of the information element is registered in the response destination table TBH (decision 125).
), when the result of judgment 125 is NO, it is the case of the above-mentioned case (■), so the response is to send a release completion message REI, COMP with data set in the "User-User" information element indicating "Call solicitation not possible". Process 126) Call recovery.

When the result of judgment 125 is YES, it is checked whether the absence mode flag FNA of the terminal status information STA is set and the absence mode is set (decision 127).
, When the result of judgment 127 is YES, it is the case of the above-mentioned case (■), so it responds with a release completion message REI, COMP in which data indicating "not at home, available for call solicitation" is set in the "user/user" information element. (processing 1
28), the call is temporarily restored.

Then, it waits until a certain period of time has elapsed (process 129) to place a call to the destination that requested the call invitation (process 130), and waits until the operator of the other party picks up the handset 10 and sends out the response message C0NN (decision 131).
No loop).

If the result of judgment 131 is YES, the process moves to process 113, and the answering machine performs the same answering operation as the receiving operation when setting the answering mode.

When the result of judgment 127 is No, it is the case of the above-mentioned case (■), so a release completion message REL-COMP is responded with data indicating "at home, available for call solicitation" set in the "user-user" information element. (Processing 132
), the call will be restored once.

Then, it waits until a certain period of time has elapsed (process 133) to place a call to the destination that requested the call invitation (process 134), and waits until the operator of the other party picks up the handset 10 and sends out a response message C0NN (judgment 135).
No loop).

If the result of the judgment 135 is YES, the tone generation circuit 5
Process 136) of outputting a ring tone output from the monitor speaker 6 to call the operator;
is repeated until the operator picks up the handset 10 and goes off-hook (No loop at decision 137).

When off-hook is detected and the result of judgment 137 becomes YES, the call between the operators ends, and either the operator of the own terminal returns the handset 10 and goes on-hook first, or the operator of the other terminal returns the handset 10 first. on-hook and disconnect message DI from ISDN.
Wait until SC is received (N in decisions 138 and 139)
o loop).

When the result of judgment 138 is YES, the process moves to process 110, and when the result of judgment 139 becomes YES, the process moves to process 111 to restore the call.

As described above, in this embodiment, by soliciting a call from the calling side's telephone, the called side switches to the calling terminal and calls the first calling side's telephone. The call intended by the operator on the calling side can be made at the expense of the other party.

In addition, the operator of the first calling party can complete the operation by simply turning on the solicitation key and entering the destination telephone number without picking up the telephone handset. The operator is called for the first time when the operator on the other end (i.e., the original calling party) answers the calling operation automatically performed by the operator's telephone.
There is no knowledge of the call originating from the first calling party, so it is easy to use in the call solicitation mode.

In addition, since the operator on the first calling side can know the status of the destination telephone, he can immediately take measures according to the status, and can perform appropriate operations during a call.

Also, even in the call solicitation mode, the answering machine function is used, so even when the destination operator is absent, the message to be transmitted can be sent at the other party's charge, which is convenient.

In the embodiments described above, the present invention is applied to a telephone, but the present invention can be similarly applied to other industrial SDN terminal devices.

[Effects of the Invention] As explained above, according to the present invention, a call solicitation mode is introduced, and a terminal that has made a call in such mode temporarily restores the call, and then makes a call in the call solicitation mode. Since the terminal that has received the call makes a call and charges are made to the terminal itself, it is possible to arbitrarily set which terminal is charged for one communication.
To obtain the effect of improving the usability of an SDN terminal device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an ISDN telephone according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing an example of the configuration of an operation display section, and FIG. 3(a) is a schematic diagram showing an example of terminal status information. ,
4(b) is a schematic diagram showing an example of a response destination table, FIG. 4(a) is a time chart illustrating a general transmission procedure of an ISDN telephone, and FIG. 4(b) is another example of a call recovery procedure. 5(a) is a schematic diagram illustrating the signal format of a message for a call setup procedure, FIG. 5(b) is a schematic diagram illustrating an example of information elements of a call setup message, and FIG. ) is a schematic diagram showing an example of information elements of a release completion message, FIG. 6 is a time chart showing an example of a transmission procedure in call solicitation mode, and FIG. 7 is a time chart showing an example of a transmission procedure in the case of a wrong number. FIGS. 8(a) to 8(c) are flowcharts showing an example of processing performed by the apparatus shown in FIG. 1 when detecting an incoming call. 1...CPU (central processing unit), 2...ROM (read only memory), 3...RAM (random memory)
access memory), 4... operation display section, 12...
Audio encoding/synthesizing device, 13... Audio memory device, 14
,15.16...Switcher. Fig.1 TEa TEa Fig. / ' Fig. tC 禾 fig SDN Eb SDN TEa Fig. (a) Tip water 5DN 4 gougi (b) Fig. (a) (b) (C)

Claims (2)

[Claims] (1) In a transmission control method for an ISDN terminal device that uses ISDN for transmission, if a calling terminal performs a call operation while setting a call invitation mode in which it invites a called terminal to make a call to its own terminal. . A transmission control method for an ISDN terminal device, wherein the called terminal calls the calling terminal that has been invited to make the call after the called terminal has once restored the call. (2) In a transmission control method for an ISDN terminal device equipped with an answering machine function and using ISDN as a transmission path, a state in which a calling terminal sets a call solicitation mode in which the calling terminal invites the called terminal to make a call to its own terminal. When you perform a call operation, the called terminal calls the calling terminal that solicited the call after the call is restored, and if the answering machine mode is set at that time, the called terminal operates an answering machine for the other party's terminal. A transmission control method for an ISDN terminal device, characterized by performing the following steps.