JP3668903B2 - Automatic loop starting method and apparatus - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method and apparatus for automatically holding a telephone by on-hooking it during a call with an outside line, and more particularly to an apparatus used for external exchange using an NTT triophone service.
[0002]
[Prior art]
Conventionally, the triophone service provided by NTT as a kind of simultaneous call system is one in which three parties can talk at the same time using a telephone line (outside line) centered on a contractor. In other words, the triophone service means that if a contractor hooks (first hooking) during a call with one external line, the station holds the external line, then calls another external line and hooks again (first When the second hooking is performed, the hold of one outside line is canceled and a three-party call can be made. In this case, it does not matter whether the other two are contractors.
[0003]
However, in the trio phone service, when the subscriber turns on his / her telephone, all lines are disconnected. Therefore, the present inventor has established a DC loop on a contractor side line by a certain means so that a call between two outside lines can be maintained even if the own telephone is on-hooked, and the outside line using the triophone service is maintained. A technology for exchanging was developed (Japanese Patent Laid-Open No. 4-94245). This utilizes a DTMF signal transmitted from itself or a partner telephone as means for closing (forming) a DC loop. However, in this case, if the telephone is off-hooked again, it is possible to hear the call between the two outsiders. In order to prevent this, a technology has also been developed in which a line is cut off closer to the end than the DC loop closed location by the DTMF signal to make it a secret story (Japanese Patent Application No. 5-269903).
[0004]
[Problems to be solved by the invention]
However, some types of telephones cannot transmit a DTMF signal. In addition, storing a push button combination that emits a specific DTMF signal for closing the DC loop requires considerable effort, and many people do not know the push button combination. Further, if this outside line exchange apparatus is installed by one or two other parties, this DTMF signal also puts other lines on hold, and there is a possibility that a telephone call cannot be made at all.
[0005]
[Means for Solving the Problems]
The present invention has been made to solve the above-mentioned problem. During a call with one outside line, the hooking of the own telephone and the reversal of the polarity of the telephone line are within the allowable hooking time by on-hook of the own telephone. To close the DC loop and put the telephone line on hold, and as a result, send the second hooking signal (this is defined as on-hook momentary interruption) It is used to exchange outside lines.
[0006]
In this way, the operator who exchanges the outside line can exchange the outside line by an extremely simple operation of calling on another hook and informing that the exchange is to be made and then on-hooking. Therefore, the second hooking operation, such as hooking or sending out a DTMF signal, becomes unnecessary, and the operation is simplified. Note that the hold according to the present invention is different from the hold in the conventional telephone. The hold in a conventional telephone is a thing that cannot be used in the present invention because a hold sound is transmitted, which hinders a call between two outside lines. The above-mentioned office line circuit is a part of a telephone line and is a part inside the device of the present invention. The present invention is mainly intended for the triophone service currently provided by NTT, but can be applied to various call services that will be developed in the future that require holding their own telephone line. There is also sex.
[0007]
Hereinafter, the present invention will be described taking the case of using the triophone service as an example. The triophone service is a call service as described above. When the DC loop is closed with the device of the present invention connected to its own phone line and the line is put on hold, the call between the two parties on the outside line is completed. To do. As a result, this can be said to be manual external line exchange using the triophone service.
[0008]
In the present invention, a telephone terminal refers to a telephone such as a single telephone or a multi-function telephone, a telephone having a plurality of extension telephones such as a button telephone (business phone) and a home telephone, a private branch exchange such as a PBX, and a number of extension telephones. This means various telephone devices that can be used. A telephone refers to a single telephone, an extension telephone, a fax machine or the like equipped with a handset. The apparatus according to the present invention is connected between the central office switch and the telephone, but these functions can be incorporated into the private branch exchange, the individual telephone, or each extension telephone. Further, the function may be incorporated in the central office switch itself.
[0009]
Hooking (instantaneous interruption) instantaneously disconnects the office line and the telephone circuit, and is a kind of signal to the central office switch. In the case of the triophone service, the hold (by the first hooking) and the release of the hold (by the second hooking) are performed in the exchange of the one external telephone. Normally, this is done by pressing the hook for a short time (100 to 1,500 ms in the standard, usually 700 to 1,000 ms), but some phones have a special hooking button. Polarity reversal means that the potential between two office lines of the line on which a call is placed is reversed between plus and minus, whereby the central office exchange charges. When the call ends, the polarity is restored.
[0010]
On the other hand, the off-hook (OFF-HOOK) means a state in which the handset is removed and a DC loop is created in the telephone so that signals can be exchanged with the central office switch. On-hook (ON-HOOK) refers to a state in which the DC loop in the telephone is disconnected by applying a handset. In the present invention, the on-hook state is measured, and if the on-hook state continues for a predetermined time, it is determined that the on-hook instantaneous interruption should be performed, and the DC loop is closed in the device of the present invention. As a result, the central office switch determines that a second hooking signal has been received. This time is determined based on the above hooking standard and is 100 ms or more and 1,500 ms or less, but it is desirable to set it to about 700 to 1,000 ms in anticipation of safety.
[0011]
However, two preconditions are necessary for an on-hook instantaneous interruption (a DC loop is closed). The first is that there was a first hooking on the own telephone, and the second is that the polarity of the telephone line is reversed. This is to prevent malfunctions of similar devices installed in the two external telephone lines. That is, in the case of one outside line that has been applied to itself, polarity reversal has occurred but hooking has not been performed. When a call is made from the self to the one outside line, polarity inversion does not occur in the one outside line. On the other hand, in the case of another outside line that is the exchange destination, no polarity reversal occurs and no hooking is performed. Therefore, even if the same device is installed in the telephones of both external lines, the two conditions are not satisfied, and even if the telephones are on-hooked, the DC loop is not closed on those lines.
[0012]
When the telephone is on-hooked after the above two conditions, the DC loop is automatically closed in the device of the present invention after 100 ms to 1,500 ms, more preferably after about 700 to 1,000 ms. The own line is put on hold. This results in the same thing as a second hooking. For this reason, the hold of one outside line held on the central office side is released, and the three-party call in the triophone service is started. However, since the own line is put on hold, the state of the triophone service is maintained even if the own telephone continues to be on-hook, and the two parties on the outside line except for the self can continue talking.
[0013]
The above will be described with reference to the drawings. FIG. 1 shows the state of current flowing through the self-phone line, and is 0 in the case of on-hook (position in FIG. 1A). When the handset is picked up (off-hook: talking with one outside line), a predetermined current flows (position in FIG. 1B). Next, the current becomes zero for a predetermined time by the first hooking (holding by the exchange of one outside line), and the state immediately returns to the state where the current flows (position in FIG. 1C). Next, another outside line is called (dial pulse or PB sound: state shown in FIG. 1D) to make a call. In the above process, the polarity of the own telephone line is reversed. When on-hook in this state, the connection with the central office switch is broken and the current becomes zero (position in FIG. 1E). When this state continues for a predetermined time (allowable hooking time: 100 ms to 1,500 ms, usually 700 to 1,000 ms), the loop control unit automatically closes the DC loop in the local circuit in the equipment and A hold state is set (the state shown in FIG. 1F). However, the on-hook state (state shown in FIG. 1G) continues. This E corresponds to the second hooking signal (on-hook instantaneous interruption). By the second hooking, the triophone service is started, and a call (external line exchange) between one external line and another external line is started.
[0014]
If the on-hook state after FIG. 1E continues for 1.5 to 2.2 seconds (reference value) or longer, a disconnection signal is transmitted from the telephone device to the central office switch. However, in the case of the present invention, since the line is put on hold before that, the disconnection signal is not transmitted and the call state is maintained. Then, when the communication between the external lines is completed and the telephones are on-hooked, the polarity of the telephone line of the own line is restored to the original state. The return or other end signal is detected by the device of the present invention, and the DC loop is released. Since the own telephone is in an on-hook state, the own telephone is disconnected from the central office switch.
[0015]
The above explanation is for the case where the outside line exchange operation is performed smoothly. However, after placing one outside line on hold (at the station side) in the first (first) hooking, dialing another outside line is missed. For example, if the operation fails, hooking must be performed to clear the operation. Since one outside line is released from the hold by this hooking (second time), the fact is notified to the other party and hooked again (third time). As a result, the state returns to the state where the first hooking has been performed. If dial mistakes occur multiple times, the same operation may be repeated each time. If it is wrong after calling another outside line, the second and third hooks are performed in a similar manner after waiting for the other party to disconnect.
[0016]
By the way, in the case of instantaneous on-hook disconnection, it is necessary that the closed state of the DC loop continues until the end of the talk. On the other hand, hooking is a kind of on-hook operation in a very short time. Therefore, depending on the hooking time (manually or setting by the hooking button), there is a possibility that the DC loop is closed in the same manner as the on-hook instantaneous interruption. If the DC loop is continuously closed (telephone line hold) in the device of the present invention by the second hooking operation due to a dial mistake or the like, the third hooking signal cannot be transmitted. If the DC loop continues to be closed at the third hooking, the second hooking (on-hook instantaneous interruption) after calling another outside line becomes impossible. Similarly, if the DC loop continues to be closed in the first hooking, the central office switch will not accept subsequent hooking signals.
[0017]
In order to solve such a situation, any of the following measures may be taken. The first is that the telephone monitoring / reception unit sets the state of the hook in as long as possible within 1,500 ms from the time when the office line and the telephone circuit are disconnected, for example, 1,200 ms or 1,400 ms (position J in FIG. 2). If it is monitored and it is off-hook (Fig. 2 (a)), it is judged that it is hooking [the second time (H in Fig. 2) or the third time (I in Fig. 2)] and the DC loop is not closed. In the state (Fig. 2 (b)), the DC loop is closed promptly (within 1,500ms). By closing the DC loop, an on-hook instantaneous interruption, which is the second hooking, is performed. The second is whether the DC loop is automatically closed within a specified time (1,500 ms), preferably about 700 to 1,000 ms, whether on-hook or hooking, and then about 1-2 seconds after on-hook or hooking (J The telephone monitor / receiver monitors the state of the hook at a predetermined time (position before and after the position). If the hook is off-hook, the hook is determined to be hooked and the DC loop is opened. If the hook is on-hook, the DC loop is kept closed.
[0018]
On the other hand, even if the own telephone line is put on hold, if the telephone is off-hooked again, it is possible to hear the call between the two outsiders, and the secret of the call may be violated. In order to prevent this, it is advisable to disconnect the office line on the end side of the DC loop closed location so as to be in the secret state. The secret story means that the telephone line during the call cannot be interrupted. On the other hand, the secret story of the present invention means that the installer side cannot participate in the exchange contents of the exchanged external lines.
[0019]
Next, the configuration of the device of the present invention will be described. First, the station line monitoring and receiving unit monitors the hooking signal and monitors the polarity of the line.It is built in parallel to the station line circuit in the device, and when the hooking signal is detected or polarity inversion occurs, the control unit A signal is output. This office line monitoring and receiving unit is generally configured by incorporating components used in the receiving unit, a driving circuit thereof, a signal transmission circuit, and the like.
[0020]
The telephone monitor / receiver is incorporated in a portion near the end of the office line circuit in the apparatus and monitors whether the own telephone is in an on-hook state or an off-hook state. That is, in the case of off-hook, the telephone-side loop is closed and connected to the central office switch, and as shown in FIG. 1, a predetermined voltage (theoretical 48V) is applied to the telephone monitor / receiver and current flows (position in FIG. 1B). In the case of on-hook, the connection with the central office switch is broken, and the voltage and current are both zero (position in FIG. 1A), and this state continues. The presence or absence of this voltage or current is detected, and the result is output to the control unit. This receiving unit is also configured by incorporating components generally used in the receiving unit, a driving circuit thereof, a signal transmission circuit, and the like.
[0021]
The loop control unit is incorporated in parallel with the local line circuit, closes the DC loop in the local line circuit in the apparatus, puts the line on hold, and releases the line to release the hold. The DC loop is closed by a control signal from the control unit. The loop control unit includes a relay (loop relay) for closing the loop and a drive circuit thereof. Instead of the relay, a thyristor or a semiconductor element that functions in the same manner may be used. Alternatively, as this loop control unit, a part of the functions of a telephone transfer device for a two-station line that has been commercially available in the past (a line hold function or a station line monitoring function) may be used. In other words, this type of transfer device employs a configuration in which the incoming line and the transfer line are each held by a DC loop and are amplified together by a hybrid to secure the volume. In addition, the transfer apparatus includes a PB signal receiving unit (corresponding to a local line monitoring receiving unit in the present invention). Therefore, the telephone transfer device in which functions such as the above-described telephone monitoring and receiving unit, a control unit described later, and a secret speech control unit are incorporated can be used in the same manner as the device of the present invention.
[0022]
The secret talk control unit is provided on the path closer to the end than the loop control unit, and disconnects the local circuit in the apparatus by a control signal from the control unit. This disconnection includes literally disconnecting the office line circuit by a secret relay, and also includes substantially preventing audio current from passing through the location by inserting a large resistance. In addition to the relay, a thyristor or a semiconductor element that functions in the same manner can be used.
[0023]
The control unit is configured mainly with a microcomputer, for example, and inputs signals from the above-mentioned office line monitoring and receiving unit and telephone monitoring and receiving unit. In addition, when a hooking signal and polarity reversal are detected and it is detected that the on-hook state has continued for a predetermined time, a loop closing signal is output to the loop control unit or the closed state is maintained, and as a result, the exchange Sends a second hooking signal. The predetermined time is about 100 ms to 1,500 ms, more preferably about 700 to 1,000 ms (or 1,000 to 1,500 ms). In addition to outputting a loop release signal to the loop control unit when the end-of-call signal is detected, the entire apparatus is controlled in accordance with a program stored in advance. Furthermore, the operation signal is output to the secret control unit or the end signal is received to reset the secret control unit. It should be noted that the operation signal is output to the secret control unit simultaneously with or immediately after the loop closing signal is output to the loop control unit, and the reset signal is output simultaneously or earlier.
[0024]
The device of the present invention may be one in which various components such as the loop control unit described above are housed in a box. However, it is possible to integrate each function into an IC and incorporate it into a board, or to make the whole into one chip. is there. In that case, the incorporation into various telephone terminals and central office switches becomes extremely easy.
[0025]
【Example】
Next, this invention is demonstrated based on the Example shown on drawing. FIG. 3 shows an example of a connection system diagram of a manual external line switching device with an automatic loop activation function (hereinafter referred to as an automatic loop activation device) according to the present invention. In this example, the automatic loop activation device 1 is connected in front of the exchange source telephone 2 (the telephone of the triophone service contractor's telephone terminal: hereinafter referred to as the exchange source). This telephone line (office line, subscriber line) 3 is connected to another external line telephone terminal via a telephone exchange network 4. Note that automatic loop activation devices 7 and 8 of the same type as the automatic loop activation device 1 are also installed in front of the caller telephone 5 and the exchange destination telephone 6. Reference numeral 3A is a telephone line on the telephone 5 side, and reference numeral 3B is a telephone line on the telephone 6 side.
[0026]
FIG. 4 is a block diagram showing an example of the automatic loop activation device 1, in which the office line monitoring receiver 9, the loop controller 10, and the telephone monitor receiver 11 are connected to the office line circuit 12. The office line circuit 12 is connected in series to the office line 3 via connection terminals L1 and L2. Reference numeral 13 denotes a control unit. Reference numerals L3 and L4 are telephone side connection terminals.
[0027]
In the following, a case where the telephone set from the caller telephone 5 (one external telephone: hereinafter referred to as the caller) to the exchange 2 is exchanged for the exchange telephone 6 (other external telephone: hereinafter referred to as the exchange) will be described. To do. If the caller 5 and the exchange 2 need to be exchanged with a third party during the call, or if the exchange is intended from the beginning, when the exchange 2 is hooked once, the caller 5 will call It is held on the exchange network 4 side, and the exchange source 2 can make a call to another. Therefore, the exchange destination 6 is called to talk.
[0028]
The state of the hooking signal and the polarity is constantly monitored by the office line monitoring / receiving unit 9. When the hooking signal and the polarity inversion are detected, the fact is output to the control unit 13. When these two conditions are satisfied and an on-hook signal is output from the telephone monitor receiving unit 11 to the control unit 13 for a predetermined time, an operation signal is output to the loop control unit 10 and a DC loop is connected to the office line circuit 12. Close. As a result, a second hooking signal is transmitted from the control unit 13 to the central office switch. In this example, the hooking signal is detected first. Conversely, when a call is made from the switching source 2 to the external line as the calling source 5, the polarity inversion is first. Therefore, the subsequent point of the two conditions is not questioned.
[0029]
By this second hooking, the hold of the caller 5 in the central office switch is released, and a three-way call becomes possible. This is a function of the triophone service. In the device according to the present invention, since the DC loop is already formed, the function of the triophone service is maintained even though the on-hook state continues, and as a result, the outside line is exchanged by connecting the transmission source 5 and the exchange destination 6. It will be.
[0030]
When the call between the transmission source 5 and the exchange destination 6 ends and both are on-hook, the polarity of the exchange source 2 is restored. When this polarity return or other end call signal is detected by the office line monitoring / receiving unit 9, a message to that effect is output to the control unit 13. Next, a DC loop release signal is output from the control unit 13 to the loop control unit 10 to release the hold state. Since the switching source telephone is in an on-hook state, a disconnection signal is output to the central office switch, and all lines are terminated.
[0031]
Next, FIG. 5 is a block diagram showing another example of the automatic loop activation device 14, in which the secret control unit 15 is incorporated near the end of the loop control unit 10. The operation signal to the secret control unit is transmitted simultaneously with the loop closing signal or with some delay, and the office line circuit 12 is disconnected. The return signal is transmitted at the same time as the loop release signal or somewhat earlier.
[0032]
The automatic loop activation device 1 of the present invention can be incorporated into various devices as shown in FIG. 6 in addition to the incorporated state shown in FIG. For example, the common circuit portion inside PBX (or button telephone device) 16 (state A in the figure), the inside of each extension telephone 17 (state B in the figure), or the office line exit of the central office 18 (see figure) It can be freely incorporated into the inside (state C) or inside (state D in the figure). However, since the current triophone service needs to be contracted for each office line, if there are a plurality of external lines (office lines) 3 as shown in FIG.
[0033]
【The invention's effect】
As described in detail above, the method of the present invention automatically closes the DC loop by on-hooking of the own telephone, on condition that the telephone of the own telephone is hooked and the polarity of the telephone line is reversed during a call with the outside line. The transmission of the second hooking signal (as a result) is achieved. Therefore, a contractor of the triophone service provided by NTT as a kind of simultaneous call system is said to go on-hook after confirming the call by turning the hooking operation and any other external number for the incoming call. With a simple operation, the outside line can be exchanged reliably. Further, when the circuit is disconnected after the on-hook to make it a secret story, it is possible to securely keep the secret of the two outside line calls. After the call between the external lines is completed, the telephone line is automatically released, so there is no need for monitoring and processing after the exchange of the external line. Cost and effort are unnecessary, and there is no psychological pressure during operation.
[0034]
In addition, since the conditions of hooking and polarity reversal are attached, even if the same type of equipment is installed on the external line telephone, only the telephone line satisfying this condition is put on hold, and it is completely prevented that the external line exchange is disconnected. Is done.
[0035]
On the other hand, the device of the present invention includes a loop control unit that closes a DC loop in a station line circuit, a station line monitoring receiver unit that detects a hooking signal and monitors polarity, and a telephone monitor that monitors whether the own telephone is on-hook or off-hook. The present invention embodies an external line exchange method that is extremely simple to operate using a triophone service, with a very simple configuration comprising a receiving unit and a control unit that exchanges signals with the receiving unit. Therefore, since a DTMF signal or the like is not used for the operation, it can be applied to any type of telephone, can be easily incorporated into a central office switch or a telephone terminal itself, and can be manufactured at low cost.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a state of a current flowing through a self-telephone line.
FIG. 2 is an explanatory diagram showing a state of a current flowing through a self-telephone line, and shows a case where on-hook and hooking are distinguished.
FIG. 3 is an example of a connection system diagram of an automatic loop starter according to the present invention.
FIG. 4 is a block diagram illustrating an example of an automatic loop activation device.
FIG. 5 is a block diagram showing another example of an automatic loop activation device.
FIG. 6 is a connection system diagram showing different installation locations of the automatic loop activation device.
FIG. 7 is a system diagram showing how to connect the device of the present invention when there are a plurality of telephone lines.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Automatic loop starting apparatus 2 Transfer origin telephone 3 Telephone line 4 Telephone switching network 5 Origination telephone 6 Transfer destination telephone 9 Office line monitoring receiving part 10 Loop control part 11 Telephone monitoring receiving part 12 Office line circuit 13 Control part 14 Automatic loop starting Device 15 Secret Story Control Unit

Claims (5)

During a call between a telephone connected to one external line and a self-phone connected to a line for which a three-party call service is subscribed, the first hooking is performed by a normal hooking operation of the self-phone. On the condition that the outside line is held on the station side and the polarity of the own telephone line is reversed, a telephone connected to the other outside line is called and a telephone call is made. The automatic loop starter which is cut off and disconnected from the central office switch and is incorporated in the telephone, private branch exchange , central office switch or connected between the telephone and the switch within 100 to 1500 ms which is the allowable hooking time. Automatically closes the DC loop, puts the telephone line on hold, restores the connection to the exchange, and disconnects from the exchange. Automatic loop start method characterized by a change in current between the recovery, the second hooking signal for releasing the hold on the station side of the one of the outside line.   2. The automatic loop activation method according to claim 1, wherein the DC loop is released and the call state of the own telephone is terminated by on-hooking one telephone line or the other telephone connected to another external line.   2. The DC loop is closed simultaneously or immediately thereafter, and the secret line control unit located on the side of the self-telephone with respect to the loop forming part is disconnected to form the secret state of the self-phone. Or the automatic loop starting method of Claim 2. A device that is connected between a central office switch and a telephone or is incorporated in a central office switch or a telephone terminal, and puts its own telephone line on hold during a call with an external line, and a direct current is connected to the central office circuit in the apparatus Loop control unit for closing a loop, office line monitoring / receiving unit for detecting a hooking signal and monitoring polarity, telephone monitoring / receiving unit for monitoring whether the own telephone is on-hook or off-hook, the station-line monitoring / receiving unit, and the telephone When the signal from the monitoring receiver is input and the first hooking signal and polarity reversal are detected and it is detected that the on-hook state is maintained within 100 to 1500 ms which is the allowable hooking time, the loop control unit closes the loop. The output signal is output, the change in current between the on-hook start and the loop closing is output as the second hooking signal, and then the loop is detected when the end signal is detected. Automatic loop starting apparatus characterized by being configured to include a control unit for outputting a loop release signal to the control unit.   5. The automatic loop activation according to claim 4, wherein a secret talk control section for disconnecting the office line circuit in the apparatus is provided closer to the self-telephone than the loop control section, and the secret talk control section is operated and returned by a signal from the control section. apparatus.

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