JPH04196860A - Incoming terminal identifying device - Google Patents

Abstract

PURPOSE:To be operated as if only one terminal is connected to one telephone circuit when an originator does not know the function of an incoming terminal identifying device by keeping the telephone circuit connected to a first incoming terminal, as it is if a selective signal from an originating side is not detected. CONSTITUTION:When the originating side is a personal computer and sends a CST signal, a CPU 132 detects that the originating side is the personal computer by a CST detecting circuit 113, opens an automatic answering telephone set 103 and calls the personal computer 106 of an extension line 120 set to a terminal attribute setting switch 130. Then, if the selective signal from the originating side is not detected, by connecting the telephone circuit 107 with the automatic answering telephone set 103, as it is and when a transmitter does not know the function of an incoming terminal identifying device 101, it operates as if only one terminal is connected to one telephone circuit 107. Thus, when the originator does not know the function of the incoming terminal identifying device 101, the automatic answering telephone set 103 is connected easily and the handle ability is improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a telephone terminal, and in particular, a single telephone line accommodates a plurality of terminal equipment such as an answering machine, a teleconverter, and a FAX. The present invention relates to a receiving terminal identification device that can selectively receive calls.

[Conventional technology]

In response to a call from a telephone line, a conventional called terminal identification device first tentatively receives the call, and then calls each terminal in response to a selection signal from the calling side. In addition, related devices of this type include Japanese Patent Application Laid-Open No.
56158 and the like.

[Problem to be solved by the invention]

In the above conventional technology, when a call is received from a telephone line, the called terminal identification device tentatively receives the call, so if the caller does not know the functions of the called terminal identification device, it is necessary to send guidance, and Follow that guidance.
This method requires operations such as sending out a B-fold signal, which poses a problem in that it is not easy to use. Further, there is a problem in that it takes time from the time when the receiving terminal identification device tentatively receives a call until the target terminal responds, and charges are incurred during that time.

An object of the present invention is to provide a called terminal identification device that operates as if only one terminal is connected to one telephone line when the caller does not know the functions of the called terminal identification device. be.

Another object of the present invention is to eliminate non-delivery charges when the caller does not know the function of the called terminal identification device.

A further object of the present invention is to eliminate the need for a voice guidance sending function and to construct a called terminal identification device at low cost.

[Means for solving the problem] 1. In order to achieve the above object, a call detecting means for detecting a calling signal from a telephone office, a means for tentatively receiving a call from a telephone office, and a means for detecting a selection signal sent from the caller side are provided. In a called terminal identification device comprising a selection signal detection means, a hook means for detecting the hook state of each terminal, and a calling signal generation means for notifying each terminal of a call, the type of the connected terminal is set. and a first terminal for setting which terminal is to be connected first in response to a call signal from a telephone line.
Incoming call terminal setting means is provided.

2. In order to achieve the above purpose, there is provided a call detection means for detecting a call signal from a telephone office, a means for provisionally receiving a call from a telephone office, and a means for detecting a selection signal sent from the caller side. In a called terminal identification device comprising a selection signal detection means for detecting the hook state of each terminal, a hook detection means for detecting the hook state of each terminal, and a calling signal generation means for notifying each terminal of a call, the type of the connected terminal is detected. a terminal attribute setting means for setting a terminal attribute, a mode setting means for setting a home mode or an out-of-home mode; and a mode setting means for setting an at-home mode or an out-of-home mode; a first incoming call terminal setting means for when out of home setting for setting whether to connect to a telephone line; and a calling when at home setting means for setting which terminal is to be called in response to a call signal from a telephone line when the mode setting means has set the at-home mode. Terminal setting means is provided.

[Effect]

1. When the terminal set by the first incoming terminal setting means is connected to the telephone line in response to a call signal from the telephone line, and the hook detecting means detects that the first incoming designated terminal has responded, The selection signal detection means is connected in parallel to the telephone line, and if a selection signal of another terminal is detected from the calling side, the designated terminal is called by the ring tone generation means, and when this terminal answers, the telephone line is connected to the telephone line. The caller can connect the called terminal identification device by disconnecting the telephone line from the first called terminal and connecting to the designated terminal, and if no selection signal from the calling party is detected, the telephone line remains connected to the first called terminal. If you don't know the features of
It operates as if only one terminal was connected to one telephone line.

2. Connecting the terminal set by the out-of-home first incoming terminal setting means to the telephone line in response to a call signal from the telephone line when the out-of-home mode is set by the mode setting means, and detecting the hook; When the means detects that the first incoming call designated terminal responds when out, the selection signal detection means is connected in parallel to the telephone line, and if a selection signal of another terminal is detected from the calling side, the ringing tone is generated. means calls a designated terminal, and when this terminal answers, the telephone line is released from the first receiving terminal at the time of going out and connected to the designated terminal, and if a selection signal from the calling party is not detected, the telephone line is connected to the designated terminal. When the device is left connected to the first incoming call terminal when going out, and the at-home mode is set by the mode setting means, in response to a call signal from the telephone line, the terminal set by the at-home calling terminal setting means is set. When connected to the telephone line, and when the hook detecting means detects that the at-home calling terminal has responded, the selection signal detecting means is connected in parallel to the telephone line, and if a selection signal of another terminal is received from the calling side. If detected, the designated terminal is called by the ringing tone generation means, and when this terminal answers, the telephone line is released from the at-home calling terminal and connected to the designated terminal, and if no selection signal from the calling party is detected. By leaving the telephone line connected to the at-home calling terminal, if the caller does not know the function of the called terminal identification device, it will appear as if only one terminal is connected to one telephone line. works.

〔Example〕

(Example 1) Hereinafter, a first example of the present invention will be described in detail with reference to FIG. In FIG. 1, 101 is a called terminal identification device according to the present invention, 102 is a general telephone, 103 is an answering machine, 104 is a facsimile (hereinafter abbreviated as FAX), 1
05 is a telecontroller (hereinafter abbreviated as telecontroller),
106 is a personal computer (hereinafter referred to as a personal computer), 107 is a telephone line, 108 is a calling signal detection circuit for detecting a calling signal from a telephone office, and 109 is a line forming a direct current loop of the telephone line and providing an interface for alternating current signals. A transformer 111 is a DTMF receiver that receives a PB multiplied signal among the selection signals sent from the caller, and 112 detects a signal (hereinafter abbreviated as CNG signal) that notifies the called party that the caller is a fax machine. C.N.
G signal detection circuit 113 is a signal that notifies the receiving side that the calling side is a pan controller (hereinafter abbreviated as C8T signal)
114 is a 400H detection circuit that detects that the calling side is on-hook; 116 is a C8T signal detection circuit that detects pressure;
~120 is an extension line for connecting each terminal, 121
125 is a hook detection circuit that detects the hook state of each terminal, 126 is a power supply circuit that applies voltage when each terminal is disconnected from the telephone line 107, and 127 is a call signal for notifying each terminal of a call. Generation circuit, 128
is a 400H2 generation circuit that notifies each terminal that it has been disconnected from the telephone line 107, and 129 is an extension line 116 to 1.
20, a terminal attribute setting switch for setting the type of terminal connected; 130, a first receiving terminal setting switch 131 for setting which terminal is connected first in response to a call signal from the telephone line 108; 132 is a timer circuit for measuring timeout when calling a terminal; 132 is a CPU that controls the entire operation of the receiving terminal identification device 1;
3 to 154 are changeover switches.

Next, the operation of the first embodiment will be explained using the flowchart shown in FIG. First, as an initial setting, the user sets the type of terminal device to be connected to the extension lines 116 to 120 (for example, a FAX is connected to the extension line 118) using the terminal attribute setting switch 129. Further, when a call is received from the telephone line 107, which terminal is to be called first is set by the first incoming terminal setting switch 130. (Here, the answering machine 03 connected to the extension line 117 is set as the first incoming terminal.) It is assumed that a call from the telephone line 107 occurs under the above settings (201 in FIG. 2). Call detection circuit 1
08, the CPU 132 first closes the switch 136 and switches the first incoming terminal setting switch 130.
The answering machine 103 set to 1 is connected to the telephone line 107. (Figure 2 202). And answering machine 103
203), the CPU 32 detects the response by the hook detection circuit 122, and switches the switch 134.
and connect the line transformer 110 to the telephone line 107 in parallel. This allows the CPU to monitor the AC signal on the telephone line 107 (204 in FIG. 2).

At this time, assume that the calling side knows the function of the called terminal identification device and inputs the teleconverter selection signal from the PB double signal (
Figure 2 205). The CPU 132 is the DTMF receiver 11
1, the FB multiplied signal is analyzed, and when it is recognized as a teleconverter selection signal, the ring tone generating circuit 127 is activated, the switch 148 is closed, and the teleconverter is called. On the other hand, switch 1
41 and open the switch 136 to release the answering machine 103 from the telephone line 107 (FIG. 2 206). Then, start up the 400Hz generation circuit 128,
The switch 151 is closed and a 400 Hz signal indicating that the calling party has gone on-hook is sent to the answering machine 103.

Then, the answering machine 103 is detected by the hook detection circuit 122.
When detecting on-hook, 400H stops the generation circuit 128 and opens the switch 151.

When the hook detection circuit 124 detects that the teleconverter 105 has responded, the CPU 132 stops the ring tone generation circuit 127, opens switches 148 and 143, closes the switch 138, and connects the teleconverter 105 to the telephone line 1.7. (207 in FIG. 2).

Next, if the caller is a FAX and sends a CNG code, the CPU 132 uses the CNG detection circuit 122 to detect that the caller is a FAX, and the terminal attribute setting switch 129 determines that the FAX is connected to the extension line 118. Knowing this, the user activates the ring tone generating circuit 127, closes the switch 147, and calls the FAX. On the other hand, switch 1
41 and opens the switch 136 to disconnect the answering machine 103 from the telephone line 107 (FIG. 2, 209). Then, start up the 400H2 generation circuit 128,
The switch 151 is closed and a signal 400H indicating that the caller is on-hook is sent to the answering machine 103.

Then, the answering machine 103 is detected by the hook detection circuit 122.
When detecting on-hook, 400H stops the generation circuit 128 and opens the switch 151.

Next, the CPU 132 detects the FA by the hook detection circuit 123.
When it is detected that the FAX 104 has responded, the ring tone generation circuit 127 is stopped, switches 147 and 142 are opened, and the switch 137 is closed.
05 to the telephone line 1071 (FIG. 2, 210).

Similarly, if the sender is a personal computer and sends a C8T signal, the CPU 132 uses the C8T detection circuit 113 to detect that the sender is a personal computer (Fig. 2 (211)).
, while opening the answering machine 103 (Fig. 2 21)
2) Call the personal computer 106 of the extension line 120 set in the terminal attribute setting switch 130 (Fig.
13).

If these terminal selection signals are not input to the timer circuit 131 for the set time (214 in Fig. 2)'
, the switch 134 is opened to disconnect the line transformer 110 from the telephone line 107 (FIG. 2, 215).

In this way, according to this embodiment, if the caller does not know the function of the receiving terminal identification device, it is the same as if only an answering machine was connected, so it is easy to use (and there is no charge for missed calls). There is an effect of not having one.

Furthermore, if a terminal having a voice response means, such as an answering machine, is designated as the first receiving terminal, there is no need to have a voice response means in the receiving terminal identification device, which has the effect of making the device less expensive.

In this embodiment, the line transformer 110 is of the type that always forms a DC loop as shown in FIG.
When another terminal forms a DC loop of the telephone line 107 and only monitors the telephone line, a switch 901 may be provided to cut off the DC current as shown in FIG.

(Example 2) Hereinafter, a second example of the present invention will be described in detail with reference to FIG. 3. In FIG. 3, 301 is a switch for setting the home/away mode, 302 is a home calling terminal setting switch for setting the terminal to be called in the home mode, and 303 is the first incoming call terminal setting when going out to set the terminal to be called in the going out mode. This is a switch, and the same components as in FIG. 1 are given the same numbers.

Next, the operation of the second embodiment will be explained using the flowchart shown in FIG. First, as an initial setting, when the user receives a call from the telephone line 107 while going out, the user selects which terminal is to be called first using the first incoming call terminal setting switch 30 when going out.
3, and when a call is received from the telephone line 107 while at home, which terminal is to be called is set by the at-home call terminal setting switch 302. (Here, the general telephone 102 connected to the extension line 116 is used as the home calling terminal, and the answering machine 10 connected to the extension line 117
3 is set as the first receiving terminal when going out. ) It is assumed that a call from the telephone line 107 occurs under the above settings (401 in FIG. 4). Call detection circuit 1
The CPU 132 that detected the call by 08 is at home/
Please check the going out mode setting switch 301.
02) If the out-of-home mode is set, close the switch 136 and switch the first incoming terminal setting switch 303 when going out.
The answering machine 103 set to 1 is connected to the telephone line 107 (403 in FIG. 4). When the answering machine 103 responds (404 in FIG. 4), the CPU 32 detects the response using the hook detection circuit 122, closes the switch 134, and connects the line transformer 110 in parallel to the telephone line 17. This allows the CPU to monitor the AC signal on the telephone line 107 (405 in FIG. 4).

If the calling party knows the capabilities of the called terminal identification device and
Suppose that the teleconverter selection signal is input by the B signal (4th
Figure 406). The CPU 132 analyzes the FB signal using the DTMF receiver 111, and if it recognizes that it is a teleconverter selection signal, starts the ring tone generation circuit 127 and switches switch 1.
Close the 48 and call the telecon. On the other hand, switch 141
At the same time, the switch 136 is opened to disconnect the answering machine 103 from the telephone line 107 (Fig.
7). And 4008. The generating circuit 128 is activated, the switch 151 is closed, and a 400 Hz signal indicating that the calling party is on-hook is sent to the answering machine 103. When the hook detection circuit 122 detects that the answering machine 103 is on-hook, 400H is detected by the generation circuit 1.
28 is stopped and switch 151 is opened.

When the hook detection circuit 124 detects that the teleconverter 105 is off-hook, the CPU 132 stops the ringing tone generation circuit 127 and switches 148 and 14.
3 is opened and the switch 138 is closed to connect the teleconverter 105 to the telephone line 107 (see 207 in Fig. 2).
).

Similarly, when a CNG signal is detected,
Open the answering machine 103 to the telephone line 107 (4th
Figure 408), call FAX 104 Figure 4 409)
, and if a C8T signal is detected (410 in Figure 4)
, the answering machine 103 is disconnected from the telephone line 107 (Fig. 4 411), and the personal computer 106 is called (Fig. 4 41).
2).

If the call detection circuit 108 detects a call when the home/away mode setting switch 301 is set to the home mode, the CPU I 32 connects the general telephone 102 set to the home call terminal setting switch to the telephone line 107. (415 in Fig. 4). When the general telephone 102 receives a call (416 in FIG. 4), the CPU 13
2 detects a response by the hook detection circuit 122, closes the switch 134, and connects the line transformer 110 to the telephone line 10.
7 in parallel (405 in FIG. 4). If the calling party is FA
If the caller is a FAX, the CPU 132 uses the CNG detection circuit 112 to detect that the caller is a FAX, and automatically connects the phone line from the general telephone 102 to the FAX.
Switch to AX104 line.

In addition, in consideration of forgetting to set the home/outside mode setting switch 301, if the general telephone 102 is called a certain number of times and no call is received, the answering machine 103, which is the first receiving terminal when going out, is called. Figure 4 41
6).

In this way, according to this embodiment, if the caller does not know the function of the receiving terminal identification device, it is the same as having only an answering machine connected to the fist, so it is easy to use (and eliminates unnecessary charges). There is an effect of not having one.

Furthermore, if a terminal having a voice response means, such as an answering machine, is designated as the first receiving terminal, there is no need to have a voice response means in the receiving terminal identification device, which has the effect of making the device less expensive.

In addition, when you are at home or when you go out, in response to calls on the telephone line,
Since you can set different devices to ring separately, it also has the effect of improving usability when you are at home.

(Embodiment 3) Hereinafter, as a third embodiment of the present invention, a fifth embodiment will be described in which the connection between the incoming terminal identification device and each terminal is in the form of a bus.
This will be explained in detail with reference to FIG. 6 and FIG. In FIG. 5, 501 is the incoming terminal identification device according to this embodiment, 502 is a communication bus, 503 is a call bus, and 504 to 508 are adapters for connecting the bus and each terminal, and the configuration is the same as in FIG. 1. Objects are given the same number. FIG. 6 shows the internal configuration of the incoming terminal identification device 501 and adapters 504 and 505 in FIG. 603 is a DTMF receiver;
4 is a CNG signal detection circuit, 605 is a C8T signal detection circuit, 606 is a 400H, detection circuit, 608 to 609 are hook detection circuits that detect the hook state of each terminal, 610 to
611 is a power supply circuit that supplies power when each terminal is disconnected from the telephone line 107; 612 to 613 are call signal generation circuits for notifying each terminal of a call pressure; 6
14 to 615 are 400H2 generation circuits that notify each terminal that it has been disconnected from the telephone line 107, 616 is a terminal attribute setting switch for setting the type of terminal connected to the extension adapters 504 to 508, and 617 is a telephone Line 1
1st incoming terminal setting switch to set which terminal is connected first in response to the call signal from 07 Sochi, 618
is a CPU that controls the entire operation of the incoming terminal identification device 501 and communicates with the adapter via the communication bus 502;
619 to 620 are CPUs that control the entire operation of the adapter and communicate with the receiving terminal identification device 501 via the communication bus 502, and 621 to 630 are changeover switches.

Next, the operation of this embodiment will be explained using the sequence diagram shown in FIG. First, the user sets the adapter 504 to
The type of terminal device connected to 508 (for example, adapter 50
5) is set using the terminal attribute setting switch 616, and when a call is received from the telephone line 107, which terminal is to be called first is set using the first receiving terminal setting switch 17. . (Here, it is assumed that the answering machine 103 connected to the adapter 504 is set as the first incoming terminal.) Under the above settings, it is assumed that a dropout from the telephone line 107 occurs (701 in Fig. 7). . Nominal ratio detection circuit 6
01, the CPU 618 detects the call and selects the answering machine 1 set in the first incoming terminal setting switch 617.
03 to the telephone line 107, the communication bus 50
2 to the CPU 619 of the adapter 504 to receive the call (702 in FIG. 7). CPU 618 of adapter 504
After confirming that the answering machine 103 is in an unused state by the hook detection circuit 608, it sends a notification to the receiving terminal identification device 501 that the call can be received (703 in FIG. 7).
, opens switch 624 and closes switch 623. On the other hand, 〇PU6 is closes the switch 621 and connects the answering machine 103 to the telephone line 107 (704 in Fig. 7). When answering machine 103 answers, C.
The PU 619 detects the response using the hook detection circuit 608, and notifies the receiving terminal identification device 501 via the communication bus 502 (705 in FIG. 7). This causes the CPU 618 to switch 6 to monitor the AC signal on the telephone line 107.
22 and connect the line transformer 602 to the telephone line 107 in parallel.

If the sender is a FAX and sends a CNG signal (707 in FIG. 7), the CPU 61 B sends a CNG signal to the CNG detection circuit 6
04 detects that the calling side is a FAX, and the terminal attribute setting switch 616 notifies the CPU 620 of the adapter 505 to which the FAX is connected (708 in FIG.
). The CPU 620 activates the ring tone generating circuit 613, closes the switch 629, and calls the FAX. Also CPU6
18 notifies the CPU 619 of the adapter 504 to release the terminal (709 in FIG. 7). The CPU 619 closes the switch 624 and opens the switch 623 to disconnect the answering machine 103 from the telephone line 107 (710 in FIG. 7). Then, 400H, the generation circuit 614 is activated, the switch 626 is closed, and a 400H2 signal indicating that the caller is on-hook is sent to the answering machine 103.

Then, the answering machine 103 is detected by the hook detection circuit 608.
When detecting on-hook, 400H stops the generation circuit 614 and opens the switch 626.

On the other hand, the CPU 620 of the adapter 505 is connected to the hook detection circuit 6.
09 detects that the FAX 104 is off-hook, the ring tone generation circuit 613 is stopped and the switch 6 is turned off.
28 and 629 are opened, and switch 627 is opened.
, connect the FAXI 05 to the telephone line 107, and notify the incoming call identification device 501 (711 in FIG. 7).

In this way, according to this embodiment, if the caller does not know the function of the receiving terminal identification device, it is the same as if only an answering machine was connected, so it is easy to use and there is no charge for missed calls. There is an effect.

Furthermore, if a terminal having a voice response means, such as an answering machine, is designated as the first receiving terminal, there is no need to have a voice response means in the receiving terminal identification device, which has the effect of making the device less expensive.

Furthermore, since the wiring between the incoming terminal identification device and each terminal is in the form of a bus, there is also the effect that the wiring is easy.

[Effects of the Invention] As described above, according to the present invention, if the caller does not know the function of the receiving terminal identification device, it is the same as if only an answering machine was connected, so it is easy to use and there is no problem. This has the effect of not requiring any outgoing fees.

Furthermore, if a terminal having a voice response means, such as an answering machine, is designated as the first receiving terminal, there is no need to have a voice response means in the receiving terminal identification device, which has the effect of making the device less expensive.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a first embodiment of the present invention, FIG. 2 is a flow chart showing the operation of the first embodiment of the present invention, and FIG.
4 is a flow chart showing the operation of the second embodiment of the present invention. FIG. 5 is an overall configuration diagram of the third embodiment of the present invention. 6 is a detailed configuration diagram of the third embodiment of the present invention, FIG. 7 is a sequence diagram showing the operation of the third embodiment of the present invention, FIG. 8 is a configuration diagram of a line transformer, and FIG. 9 is a direct current FIG. 2 is a configuration diagram of a line transformer that does not form a loop. Explanation of symbols 108...Call detection circuit, 110...Line transformer, 111...DTMF receiver, 112...C
NG detection circuit, 113... C8T detection circuit, 114...
・400H, Detection circuit, 130... 1st chargeable terminal setting switch, 129... Terminal attribute setting switch, 301... Home/outside setting switch, $ 2 Figure 4 Figure 5 Record 8 Figure $ 9 Record

Claims (1)

[Scope of Claims] 1. Call detection means for detecting a call signal from a telephone office; means for temporarily receiving a call from a telephone office;
A receiving terminal comprising a selection signal detection means for detecting a selection signal sent from the caller side, a hook detection means for detecting the hook state of each terminal, and a calling signal generation means for notifying each terminal of a call. The identification device includes a terminal attribute setting means for setting the type of the connected terminal, and a first receiving terminal setting means for setting which terminal is connected first in response to a call signal from the telephone line. connecting the terminal set by the first incoming terminal setting means to the telephone line in response to a call signal from the telephone line; and when the hook detecting means detects that the first designated incoming terminal has responded; The selection signal detection means is connected in parallel to the telephone line, and if a selection signal of another terminal is detected from the calling side, the ring tone generation means calls the designated terminal, and when this terminal answers, the telephone line is switched to the telephone line. The incoming call is configured such that the telephone line is released from the first receiving terminal and connected to the designated terminal, and if a selection signal from the calling party is not detected, the telephone line is kept connected to the first receiving terminal. Terminal identification device. 2. A call detection means for detecting a call signal from a telephone office, a means for provisionally receiving a call from a telephone office, a selection signal detection means for detecting a selection signal sent from the caller side, and each terminal. In a called terminal identification device comprising hook detection means for detecting a hook state of a terminal, and call signal generation means for notifying each terminal of a call, the terminal attribute setting means for setting the type of connected terminal; , a mode setting means for setting a home mode or an out-of-home mode; and an out-of-home setting for setting which terminal is connected first in response to a call signal from a telephone line when the out-of-home mode is set by the mode setting means. a first incoming call terminal setting means; and an at-home calling terminal setting means for setting which terminal is to be called in response to a call signal from a telephone line when the at-home mode is set by the mode setting means; When the out-of-home mode is set by the setting means, the terminal set by the out-of-home first receiving terminal setting means is connected to the telephone line in response to a call signal from the telephone line, and the hook detecting means detects the out-of-home mode. When it is detected that the first designated receiving terminal has answered, the selection signal detection means is connected in parallel to the telephone line, and if a selection signal of another terminal is detected from the calling side, the designated terminal is activated by the ringing tone generating means. When this terminal answers, the telephone line is released from the first incoming terminal at the time of going out and connected to the designated terminal, and if a selection signal from the calling party is not detected, the telephone line is disconnected from the first incoming terminal at the time of going out. In response to a call signal from the telephone line while the terminal remains connected to the incoming call terminal and the at-home mode is set by the mode setting means, the terminal set by the at-home calling terminal setting means is connected to the telephone line. When the hook detection means detects that the at-home paging terminal has responded, the selection signal detection means is connected in parallel to the telephone line, and if a selection signal of another terminal is detected from the calling side, the A designated terminal is called by the ringing tone generating means, and when this terminal answers, the telephone line is released from the at-home calling terminal and connected to the designated terminal, and if a selection signal from the caller is not detected, the telephone line is disconnected. A receiving terminal identification device characterized in that it is configured to remain connected to the calling terminal when the user is at home. 3. The receiving terminal identification device according to claim 1, wherein the connection between the receiving terminal identification device and each terminal is in the form of a bus.