JP2843554B2 - Method and apparatus for displaying information about a receiving terminal on a transmitting terminal, and an exchange - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is better to display the call control signal independently of the call, and using a signaling that obtained by transmitting including additional information, the information about the called terminal to the calling terminal
Information about the law, its equipment, and the terminating terminal
It relates to the terminating exchange as displayed on the terminal .

[0002]

2. Description of the Related Art One of communication systems capable of handling a large amount of call control signals.
As one, a common channel signaling method is known. At present, the common channel signaling method is generally called International Telegra
m andTelephone Consultative Committee (CCITT)
No. 7 signal system (hereinafter abbreviated as No. 7) recommended by the J.A. However, No. 7 itself has few provisions for supplementary services. Completion of Calls to Busy Subsc
viber). CCBS, CCI IT Tea Red Book, Volume
VI. Facicle VI. 8 (1984) pp. 80-82,
Page 240 (CCITT Red BookVOLUMEV)
I FASCILEVI. 8 (1984) pp80-82, p
As described in p240), this is a so-called callback service. When this function is registered when a call is made to a busy subscriber or extension, the busy subscriber or extension becomes vacant. When a call is made, both the caller and the callee receive a call from the system. However, this CC
BS is a function only when the incoming extension is busy. In general, it is wasteful to continue calling normally, for example, when the called party does not return to a seat for a while during a meeting or is away for a few days during a business trip, for example, when the called party is not busy and the incoming extension is idle. There are cases.

Further, there is a case where it is desired to confirm the name of the called party and other information about the called party before actually calling the called party.
Is not specified.

[0004] Integrated Services Digital Network
(ISDN) can handle a large amount of call control signals, but has the same problem. Japanese Patent Application Laid-Open No. 62-263743 has a means for storing the absence of a user when an extension telephone user is absent and a telephone number of a transfer destination. A technique for forwarding an incoming call first is shown. However, this technique does not solve the above problems.

Japanese Patent Application Laid-Open No. 63-178233, filed under the name of the same applicant, relates to a technology relating to a private branch exchange telephone (extension). There is disclosed a calling system in which, when a call is received, a user (caller) of a calling extension is caused to hear a sound (talkie) notifying information without calling a called extension telephone. This scheme differs from that relating to communication across multiple switches.

[0006]

In the prior art described above, even when the user of the receiving terminal is absent during a business trip or a meeting, the calling party does not know that, the call continues for a certain period of time, and there is no response. Sometimes, for the first time, the caller is guessing the absence and goes on-hook to disconnect the line. In addition, the caller does not know the situation of the receiving side, and makes a useless call again. During this useless call, the line is blocked, which hinders effective use of the line. In order to avoid such inconvenience, if the absence information of the called party is returned from the exchange on the called side to the calling side at the time of calling, the useless use of the line described above is eliminated, and The information of the called party is also transmitted to the calling party, and the communication serviceability is improved. However, at the present time, a technology for realizing such a communication service has not been developed, and this is an issue to be addressed in the future.

A first object of the present invention is to receive an incoming call to a receiving terminal.
When there is a connection request, pre-register the incoming terminal
Called party information indicating the presence / absence of the user is sent
That can be displayed on the terminal,
If the information indicates the user's location,
While calling, the called party information indicates the absence of the user
If it is, the call to the called terminal cannot be made,
The line is immediately restored without the called terminal being called.
Sends information about the called terminal that can be used
It is an object of the present invention to provide a method of displaying a message on a communication terminal .

[0008] A second object of the present invention is to receive a call to a receiving terminal.
When there is a connection request, pre-register the incoming terminal
Called party information indicating the presence / absence of the user is sent
That can be displayed on the terminal,
If the information indicates the user's location,
While calling, the called party information indicates the absence of the user
If it is, the call to the called terminal cannot be made,
The line is immediately restored without the called terminal being called.
Sends information about the called terminal that can be used
It is an object of the present invention to provide a device for displaying on a communication terminal .

A third object of the present invention is to provide an incoming call to a receiving terminal.
When there is a connection request, pre-register the incoming terminal
Called party information indicating the presence / absence of the user is sent
Can be sent to the terminal and at that time
If the information indicates the user's location,
While calling, the called party information indicates the absence of the user
If it is, the call to the called terminal cannot be made,
The line is immediately restored without the called terminal being called.
It is an object of the present invention to provide a receiving-end exchange which is designed to be old.

[0010]

The first object is to receive a call.
Using the terminating terminal for the terminating exchange accommodating the terminal
Step of registering the presence / absence of the user as called party information
And the receiving-side exchange exchanges the calling-side exchange accommodating the calling terminal.
When receiving the incoming connection request from the exchange,
Determining the terminating terminal accommodated in the device;
It is determined from the follower information that the receiving terminal can receive a call.
In this case, the calling terminal and the receiving terminal are connected to both exchanges.
Call the called terminal by connecting via the
The callee information of the terminal is transmitted to the address completion signal of the call control signal.
The originating exchange via the common line signaling path
Sending the call to the machine, and receiving the call from the callee information.
If it is determined that the terminal does not receive a call,
No call to the called terminal in order to be old
Then, the callee information of the called terminal is stored in the call control signal.
In addition to the complete call reverse direction setting signal,
Sending the call to the originating exchange.
The local exchange has a call control signal including called party information of the called terminal.
When receiving a call number, the receiver information is transmitted to the transmitting terminal.
And displaying the called party information on the calling terminal.
And displaying by the section ,
This is achieved by displaying information on the originating terminal . Also,
The purpose of 2 is to send the incoming call to the terminating exchange accommodating the terminating terminal.
The presence / absence of the user using the communication terminal as the recipient information
Means for registering, and the receiving side exchange accommodates the calling terminal
Received an incoming connection request from the originating exchange
Means for deciding the terminating terminal accommodated in the terminating exchange
From the called party information that the called terminal is ready to receive
If determined, the calling terminal and the receiving terminal are
Connected via the exchanges and called the called terminal,
The callee information of the called terminal is added to the call control signal.
Signal through the common line signal path in addition to the
Means for sending to the originating exchange, and
When it is determined that the receiving terminal is not receiving a call,
For the purpose of early recovery, call the called terminal
Without receiving the callee information of the called terminal.
Signal to the common line signal
Means for sending to the originating exchange via a path,
Call control including receiving party information of the receiving terminal by the receiving exchange.
Upon receiving a signal, sending the addressee information to the calling terminal
Output means, and a display unit of the calling terminal for displaying the called party information.
This is achieved by configuring with a means for displaying .

A third object is to provide a communication path and a receiving terminal.
Switch means for executing transmission of a call signal between the
Register the presence / absence of the user of the called terminal as called party information
Memory means for transmitting and receiving the communication path from the originating exchange.
When receiving an incoming connection request sent via
Means for determining a called terminal accommodated in the
If it is determined from the information that the receiving side terminal can receive a call,
In this case, the calling terminal and the called terminal are exchanged with each other.
Connected via a device to call the called terminal, and
The callee information of the called terminal is stored in the address of the call control signal.
In addition to the completion signal, the transmission via the common line signal path
Means for sending to the local exchange, and
If the receiving terminal determines that there is no incoming call,
Call for the terminating terminal in order to
The callee information of the called terminal to the call control
Incompletion of the signal
Means for sending to the originating exchange via a path,
When it is determined that the receiving terminal does not receive a call,
And means for cutting the road .

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the present invention in detail, the services provided by the exchange or the exchange system according to the present invention will be described. The registration information of the called party is returned from the exchange on the receiving side to the terminal, and the registered information is displayed on the calling terminal. For example, if the called party is in a meeting and is returning, the information indicating that the receiving party is in a meeting or returning is displayed on the terminal of the caller. This allows the caller to know the state of the callee, determine when the callee can be contacted, and avoid unnecessary calls. At this time, the communication line established between the calling terminal and the called terminal is automatically disconnected and restored (into an empty state), so that the line can be more effectively used. In addition, the name,
It is possible to obtain callee information such as to which department the user belongs, and to improve serviceability.

An embodiment of the present invention will now be described with reference to FIGS.
This will be described below. FIG. 1 is a configuration diagram of a system to which a receiving terminal information display method according to an embodiment of the present invention is applied.
In FIG. 1, reference numerals 1 and 1 'denote a transmitting station and a receiving station, respectively, 2 and 2' are exchange switches, 3, 3 'are central control units, 4, 4' are memories, and 5, 5 'are telephones and telephones. Transmission / reception terminals such as facsimile and data terminals, 6, 6 'are communication trunks, 7, 7' are common line signal processing devices, 8 is a communication path, and 9 is a signal path. Common line signal processor 7,
Reference numeral 7 'designates the selection and transmission of a line when transmitting the control signal generated by the central control unit 3, 3' of the station to which it belongs, reception to the central control unit when a control signal is received from another station, and others. Has functions. These are the logical configurations of the major parts of the switch connected using common channel signaling. That is, the components of a general exchange include an external storage device, a maintenance terminal, and the like in addition to those shown in the figure, but are omitted in the present embodiment because they have no direct relationship. As for the signal path 9, there is a case where a common channel signal is physically inserted into the communication path 8 as an example of the realization method, but logically, as shown in FIG. There is no difference that the common line signal processing devices of the exchanges facing each other are connected. This means that ISDN
The same applies to a case where the exchange is connected via an upper network such as a public network by an interface.

FIG. 2 is a diagram showing an example of the configuration of a communication network when an exchange is connected via an upper network by an ISDN interface. 21 and 21 'are originating stations, respectively.
22, 22 'represent exchange switches, 23, 22
23 'is a central controller, 24 and 24' are memories, 25,
Reference numeral 25 'denotes a transmitting terminal and a receiving terminal, 30, 30' an ISDN interface, and 31 an upper network. If the signal format provided by the higher-level network 31 has a function of transmitting user information transparently, the exchange 21 and the exchange 21 'communicate with each other extension information to be added to a call control signal according to the present invention described later. Can be.
Therefore, the communication network in which the exchanges are connected via the upper network such as the public network by the ISDN interface is equivalent to the communication network of the No. 7 common channel signaling system, and the present invention can be applied.

In the following description of the embodiments of the present invention, a communication network using a common channel signaling system will be described as an example.

Returning to FIG. 1, the terminals 5, 5 'shown in FIG.
It is a multifunctional telephone with a liquid crystal display function. Now, when the user of the terminal 5 '(called a called party) leaves the seat to attend a conference, first, as shown in FIG. 3, the terminal 5' is off-hook and a special number is dialed to set the terminal user state setting mode. To Then, the user dials a number indicating his / her status.
For example, if the number is “1” indicating the “in a meeting” state,
By dialing "1", the self status is registered in the exchange. Next, the return date and time are input by the same dial. Further, if there is a message (response message), the message setting mode is also set according to the special number, and an appropriate message is dialed out of a predetermined number of fixed messages by dialing the number indicating the message. select. As described above, the terminal user's status, message, etc. are input by number. Therefore, when this is sent to the destination exchange as will be described later, it is sufficient to notify this number, and when it is displayed, the number is stored in the memory. 4 may be converted to the text data stored.

As described above, the information of the called party inputted from the terminal 5 'is registered in the memory 4' of the exchange 1 '. FIG. 4 shows a format when registered in the memory 4 '. In the area corresponding to the terminal number of the terminal 5 ', the user status number a indicating the status of the called party, the number a = 1 indicating "in a conference" in the above example, and the returning month, day, hour, and minute are indicated. Numbers b, c, d, and e, respectively, and a number f, which indicates a response message, are registered.

FIG. 5 is a sequence diagram showing a connection procedure when a user of the terminal 5 calls a user of the terminal 5 '. First, the extension terminal 5 accommodated in the exchange 1 of the calling station makes a call, and then the terminal 5 dials the access number of the called terminal 5 'accommodated in the exchange 1' of the called station. When the originating station 1 accepts the dialing of the terminal 5 and recognizes the connection request to the terminating station 1 'from the access number, the originating station 1 indicates the terminating request to the terminating station 1' to the terminating station 1 '. Address message (start signal,
Incoming call) is transmitted. At the receiving station 1 ', the central controller 3' determines the receiving terminal 5 'from the address message,
Based on whether the receiving terminal is busy or idle, whether the receiving terminal specifies the call based on the call control signal described below, whether the call is disconnected, etc. Thereafter, if the incoming call is possible, an address completion signal is notified to the calling station 1, and if the incoming call is not possible, an incomplete call reverse direction setting signal (disconnection signal) is notified to the calling station 1. At this time,
The registration information of the called party is added to the address completion signal or the incomplete call reverse direction setting signal constituting the call control signal. First, the central control unit 3 'of the receiving station 1' checks whether the user of the receiving terminal 5 'has registered his / her own information, and reads out the registration information if there is any. As shown in FIGS. 6 and 7, these are set as parameters of an address completion signal and an incomplete call reverse direction setting signal.

FIG. 6 is a parameter format diagram in the case of an address completion signal. In the signal display according to the CCITT recommendation section, bitH is used to define whether or not there is extended information. In this case, since there is extended information, that is, registration information of the called party, bitH is set to “1”. still,
If there is not, this is set to “0”. As the extended information, for example, the absence reason a of the called party in 8 bits,
Returning month, day, hour, minute b, c, d, e at t × 4, 8bi
The message text size and the message text f are displayed by numbers at t and 8 bits × n.

In FIG. 6, each of b, c, d, and e is composed of 8 bits as in the case of a. However, due to restrictions on the drawing, each of b, c, d, and e is shown to be shorter than the region of a. Please note. For details of the CCITT recommendation part of the address completion signal, refer to “Signalling System No. 7”.
On page 33.

FIG. 7 shows an incomplete call reverse direction setting signal UBM (un
successful backward set-up information messag
FIG. 6 is a parameter format diagram in the case of e), in particular,
As an example, unsuccessful backward set-up inform
Extendedunsuccessful backward in the ation message
An example in which a set-up information message (EUM) is extended to carry information of a called party is shown. As in the case of FIG.
Of the signal indications according to the CITT recommendation section, the presence or absence of extended information is defined using bitH. If there is extension information, that is, registration information of the called party, bitH is set to “1”; otherwise, bitH is set to “0”. The extension information section is the same as that in FIG.

The details of the EUM format are described on page 35 of "Signalling System No. 7".
Indicates that the bitD to A columns indicate an Unsuccessful indicator, 0000 is spare, and 0001 is subscribe
This indicates r busy, and 0010 is spare in the CCITT recommendation, but in the present invention, this is used as an absence display. 0010 to 1111 is a spare. bitH
Columns E to E are spares, but in the present invention, bi
tH is used to display the presence or absence of registration information.

FIG. 8 is a sequence diagram showing a connection procedure when a call cannot be received. In this case, the called station notifies the calling station with the called party information added to the EUM. The calling station displays the obtained recipient information on the calling terminal. Next, the originating station sends a disconnection signal CLF to the terminating station to restore (empty) the line. After confirming the restoration, the called station sends a restoration confirmation signal RLG to the calling station. When the address completion signal or the incomplete call reverse direction setting signal to which the extension information is added is notified to the calling station 1, the calling station 1 looks at the extended information and displays this information on the calling terminal 5. . For example, FIG. 9 is a diagram showing a display example, in which a call number display area of one column (displayed as "1" in the illustrated example) and a call state name display area of 12 columns (CONNECTING (under connection) in the illustrated example). ), A 14-column dial monitor display area (displayed as 826654 in the illustrated example), and a 6-column received user state name display area (CONFERENCE (attend in the illustrated example).
ing a conference) and a display area with one column of detailed information (indicated by * in the example shown). If you want to know detailed information, perform a predetermined operation. Are displayed. Note that the length of each area is not proportional to the number of columns in FIG.

Note that, depending on the state of the user of the receiving terminal 5 ', an address completion signal is returned, that is, a call state is entered, or an incomplete call reverse direction setting signal is returned, that is,
Whether to cut the communication path between the calling station and the called station without setting the calling state can be determined by, for example, data shown in FIG. This is because, for example, as shown in FIG. 10, by setting one bit of the address storing the user state of the memory 4 to “1” or “0”, for example, if “1”, the user is temporarily away from the seat. Incoming and outgoing calls are made. If "0", it means that the user is on a business trip, so it is judged that calling is useless, and the call is disconnected in order to make effective use of the communication path between the stations.

Next, another embodiment of the present invention will be described with reference to FIGS. In this embodiment, the information about the called party can be read without the calling party calling the called party (called terminal).

In FIG. 11, the originator informs the exchange that a call to the terminating terminal is unnecessary and that he / she wants to obtain only the information of the terminating terminal by a special number or the like at the time of dialing. The exchange sends out extended information, that is, an address message (activation signal) to which a parameter for requesting the return of only the destination terminal information without calling the destination exchange to the terminating exchange is added. This parameter is added in the present invention. Upon receiving this, the terminating exchange adds the terminating terminal information to Facility Informacion (FAI) described later without calling the terminating terminal, and returns the information to the originating exchange. The terminating terminal information is also added in the present invention. Next, the calling exchange displays the received terminal information obtained above on the calling terminal. then,
A disconnection signal CLF is sent from the calling station to the called station to restore (empty) the line. After confirming the restoration, the called station sends a restoration confirmation signal RLG to the calling station.

FIG. 12 is a parameter format diagram of the address message. 1st additional information display byte (bitA to H columns) in the signal display according to the CCITT recommendation section
Using the bitH inside, it is defined whether or not there is extended information. For example, if extension information exists, “1” is set to bitH, and if not, “0” is set to bitH. As extended information, the facility information is displayed in 8 bits. If the value is 0, a normal call (ordinary call) is set. If the value is 1, the information of the called terminal is read without calling the called terminal. 2-255 is reserved.

FIG. 13 shows a parameter format of FAI. FAI is CCITT No.7 Tel
The signal added to the ephone User Part according to the present invention, but is defined as a national operation. Hea
The part where der0 is 1100 and Header1 is 0101 is used. In the signal display according to the CCITT recommendation section, bitH
Is used to define whether or not there is extended information (inter-network call information). In this case, since there is extension information, that is, registration information of the called party, bitH is set to “1”. If there is no data, this is set to “0”. As the extended information, similarly to the case of FIG.
Returned month, day, hour, minute b, c, d, e with 8 bits x 4,
The message text size and the message text f are displayed in numbers of 8 bits and 8 bits × n, respectively. The name and affiliation of the terminal user can be registered in the message text. To briefly explain the CCITT recommendation section, the H ₀ (header 0) field means that the heading code is H ₀ , and the H ₁ (header 1) field means that the heading code is H _1. . The inter-network call information display field is 1 byte, bits A to G are reserved, and bitH is used for indicating inter-network call information presence / absence as described above. The terminal number digit field is composed of 1 byte and represents the number of digits of the terminal number (extension number). The terminal number field consists of 3 bytes,
Indicates the terminal number. The terminal number digit field and the terminal number field are fields unique to FAI. In this manner, F shown in FIG.
Obtaining callee information from the AI and displaying it on the calling terminal,
This is possible without calling the receiving terminal.

In the above-described embodiment, a telephone is taken as an example of a terminal. However, it goes without saying that the present invention can be applied to a case where another kind of terminal equipment, for example, a facsimile or a data terminal is used.

[0030]

As described above, according to the first aspect,
If there is an incoming connection request to the receiving terminal,
The presence / absence of the user registered in advance for the receiving terminal
The callee information indicating the presence can be displayed on the calling terminal.
At that time, the called party information indicates the location of the user.
Call the called terminal while the called
If the information indicates the absence of the user, the called terminal
The incoming terminal is called as unavailable to call
The line can be restored promptly without any trouble.
A way to display information about the called device on the calling device is
According to the second aspect, the incoming connection to the incoming terminal is established.
When the request is made, the pre-registered
The receiver information indicating the presence / absence of the user
At the same time as the callee information
If the presence of the user is indicated, call the called terminal.
While the callee information indicates the absence of the user
If the call to the called terminal is not possible,
Line recovery quickly without ringing the called terminal
Information about the receiving terminal
The device for displaying at the end further comprises a receiving terminal according to claim 3.
When there is an incoming connection request to the
Recipient that indicates the presence / absence of the user, which is registered in advance
Information can be sent to the originating terminal,
If the called party information indicates the presence of the user,
While calling the called terminal, the called party information is not
The call to the called terminal is not
Yes, the incoming terminal is not called,
The receiving side exchange, which enables crab line restoration, is
Each of them has been obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a communication network capable of displaying called terminal information according to an embodiment of the present invention;

FIG. 2 is a diagram showing a configuration of a communication network capable of displaying called terminal information according to another embodiment of the present invention;

FIG. 3 is a diagram showing a procedure flow of registering information from a terminal;

FIG. 4 is a diagram showing a format when registering information is stored in a memory shown in FIG. 1;

FIG. 5 is a diagram showing a connection procedure sequence of the receiving terminal information display method according to one embodiment of the present invention;

FIG. 6 is a diagram showing a format for adding extension information to an address completion signal;

FIG. 7 shows Extended unsuccessf according to the present invention.
ul backward set-up information message (EU
M) A diagram showing a format for adding extension information to a signal.

FIG. 8 is a sequence diagram showing another embodiment of the present invention.

FIG. 9 is a diagram showing a display example;

FIG. 10 is a table diagram for discriminating between calling and line restoration depending on the state of the called party;

FIG. 11 is a sequence diagram showing still another embodiment of the present invention.

FIG. 12 is a diagram showing a parameter format of an address message.

FIG. 13 is a diagram showing a parameter format of FAI.

[Explanation of symbols]

1, 1 '... exchange, 2, 2' ... exchange switch, 3, 3 '
... Central control unit, 4,4 '... Memory, 5,5' ... Calling / receiving terminal, 6,6 '... Talk trunk, 7,7' ... Common line signal processing device, 8 ... Talk path, 9 ... Signal path

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04M 3/00 H04M 3/16-3/20 H04M 3/38-3/58 H04M 7/00-7 / 16

Claims (3)

(57) [Claims] An originating exchange accommodating an originating terminal and a destination exchange.
A connection is established between the terminating exchange accommodating the communication terminal and the exchanges.
A communication path for transmitting a call signal between stations;
Uses common signal path for transmitting call control signal of call signal
Terminating end in a configured interoffice network communication network
This is a method of displaying information about the end user on the calling terminal.
Use the terminating terminal for the terminating exchange accommodating the terminating terminal.
To register the presence / absence of the
And the receiving side exchange , wherein the receiving side exchange contains a calling terminal.
Receiving the incoming connection request from the
Determining the accommodated incoming terminal; and determining that the incoming terminal is available for receiving from the incoming callee information
In this case, the calling terminal and the receiving terminal are
Connect via the exchange, call the called terminal, and
The called party information of the called terminal is stored in the address of the call control signal.
In addition to the completion signal, the transmission via the common line signal path
Sending the call to the local exchange , and judging from the called party information that the called terminal has not received a call.
In the event that the call is terminated,
The callee of the called terminal without making a final call
Information to the incomplete call reverse direction setting signal of the call control signal.
And sent to the originating exchange via the common line signal path.
Issuing, the originating exchange includes recipient information of the terminating terminal.
When a call control signal is received, the called party information is transmitted to the transmitting end.
And displaying the called party information on a display unit of the calling terminal.
Display information about the receiving terminal consisting of the steps on the calling terminal
How . 2. An originating exchange containing an originating terminal,
A connection is established between the terminating exchange accommodating the communication terminal and the exchanges.
A communication path for transmitting a call signal between stations;
Uses common signal path for transmitting call control signal of call signal
In a configured interoffice network communication network, the terminating terminal is used for a terminating exchange accommodating the terminating terminal.
For registering the presence / absence of a user to be called as called party information
And the originating exchange , wherein the originating exchange accommodates the originating terminal.
Upon receiving an incoming connection request from, to the terminating switch
Means for determining the accommodated terminating terminal, and judging that the terminating terminal can accept the call from the called party information
In this case, the calling terminal and the receiving terminal are
Connect via the exchange, call the called terminal, and
The called party information of the called terminal is stored in the address of the call control signal.
In addition to the completion signal, the transmission via the common line signal path
Means for sending to the local exchange , and judging from the called party information that the called terminal has not received a call.
In the event that the call is terminated,
The callee of the called terminal without making a final call
Information to the incomplete call reverse direction setting signal of the call control signal.
And sent to the originating exchange via the common line signal path.
Issuing means and the originating exchange includes recipient information of the terminating terminal.
When a call control signal is received, the called party information is transmitted to the transmitting end.
And means for displaying the called party information on a display unit of the calling terminal.
Displaying information about the receiving terminal consisting of steps on the calling terminal
Equipment . 3. A communication path for transmitting a call signal between stations.
A common signal path for transmitting a call control signal of the call signal
And the receiving-side terminal to accommodate the user of the receiving-side terminal.
A display unit for displaying information about the common line signal path
Incoming call exchange sent to the originating exchange containing the originating terminal
An exchange for transmitting the call signal between the communication path and the called terminal.
And the presence / absence of the user of the called terminal as called party information.
Memory means for registering;
When receiving an incoming connection request sent via the channel
Means for determining the called terminal accommodated therein, and determining from the called party information that the called terminal is ready to receive a call.
If set, the calling terminal and the called terminal
Connect via both exchanges and call the called terminal
And transmits the called party information of the called terminal to the call control signal.
Through the common line signal path in addition to the
Means for sending to the originating exchange, and
When it is determined from the information that the receiving terminal is not receiving a call
In order to quickly restore the line,
Without receiving the callee information of the called terminal.
Is added to the incomplete call reverse setting signal of the call control signal.
It is sent to the originating exchange via the front Symbol common signaling channel Te
Means, and when the receiving side terminal is determined to be an incoming or outgoing call,
Exchange comprising means for cutting the communication path, at least.