JP2725296B2 - Call transfer device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to transmission of a DTMF signal to a central office on a call capturing side by a multi-frequency selection signal (hereinafter referred to as a DTMF signal) transmitted from a telephone of a caller. And a call transfer device for selecting a call partner.

2. Description of the Related Art A conventional call transfer device is shown in FIG. Reference numeral 100 denotes a call transfer device, which includes the following parts.

Reference numeral 103 denotes a bell detection unit that detects a bell signal transmitted from the central office 116 through the central office line 117 and the capacitor 102 for DC cutoff. The detection output of the bell detection unit 103 is input to the control unit 101 and used for incoming call determination. 104
Is a relay for capturing the station line 117, which is controlled by the control unit 101 and forms / opens a DC loop with respect to the central office exchange 116, and indicates the intention of calling, answering, or ending the call. 105 detects an instantaneous interruption of the DC loop current indicating an end of the call transmitted from the central office exchange 116 via the office line 117 (hereinafter, this instantaneous interruption of the DC loop current is referred to as a CPC signal), and notifies the control unit 101 of the interruption. This is a CPC signal detection unit to perform. The capacitor 106 cuts off the direct current of the office line 117 and transmits only the speech voice band signal to the internal speech path 124. On the other hand, a capacitor 107 connected to the office line 118, a bell detection unit 108, a relay 109, C
The PC signal detection unit 110 and the capacitor 111 are respectively a capacitor 102, a bell detection unit 103, a relay 104, and a CPC signal detection unit 10.
5. Performs the same function as the capacitor 106. Internal call path 124
Connects the capacitors 106 and 111
A signal connection is made between the telephone line 117 and the office line 118 in the voice communication band.

The telephone set 112 is a telephone set under the control of the central office 114 and is connected by the office line 113. Reference numeral 115 denotes a commercial communication line, which is specified as connecting between the central office 114 and the central office 116. The functions of the telephone 123, the office line 122, the exchange 121 and the commercial communication line 120 are as follows.
And the commercial communication line 115.

FIG. 5 is a flowchart for explaining the operation of the conventional call transfer device 100 shown in FIG.

The operation will be described below with reference to the flowchart shown in FIG. In step 201, the station line 117 is
It is determined whether or not there is an incoming call. If there is no incoming call, the next step 202 is executed, and if there is an incoming call, step 203 is executed. In step 202, the bell detector 108 determines whether there is a bell incoming call on the local line 118. If there is no incoming call, the process returns to the first step 201, and the bell incoming call monitoring of the local line 117 and the local line 118 is repeated. If the bell incoming is detected in step 202, the next step 204 is executed. In step 201, a bell call is detected on the office line 1117 in step 201, and step 2 is executed.
When the process proceeds to 03, it is determined whether or not there is a bell incoming call on the office line 118 in order to capture the transmission on the office line 118 side. Line 118
If there is a bell ringing on
And returns to step 201 to monitor the incoming call at the station line 117 and the station line 118. If there is no bell incoming call on the office line 118, the process proceeds to the next step 205 because the call can be captured, the relays 104 and 109 are turned on, the incoming call is captured on the office line 117, and the outgoing call is captured on the office line 118. In this state, the caller enters line 11 from telephone 112.
3, central office 114, commercial communication line 115, central office 116, central office
This means that a new call can be sent to the office line 118 via the communication line 117. The calling operation is DTMF sent from the telephone 112
According to signals, office line 113, office exchange 114, commercial communication line 115,
The central office switch 119 can be controlled via the central office switch 116, central office line 117, relay 104, capacitor 106, internal communication path 124, capacitor 111, relay 109, and central office line 118. Here, the central office 119 analyzes the DTMF signal transmitted from the telephone 112, selects the central office 121 via the commercial communication line 120 to receive the telephone at the telephone 123 desired by the caller, and connects the telephone 123. The central office 121 is instructed to send a bell signal to the office line 122. The call is established when the callee of the telephone 123 picks up the handset. End phone call 112
Or, it is determined by the user of the telephone 123 returning the receiver, and the central office (116 or 119) on the side where the receiver is returned
Sends a CPC signal to the call transfer device. Steps 206 and 207 are processing for detecting the CPC signal of each local line by the CPC signal detection unit (105 or 110). Steps 206 and 20 until the CPC signal is detected are performed.
Repeat 7. When a CPC signal is detected in one of these steps, the process proceeds to step 208, where the relays 104 and 109 are turned off, the office lines 117 and 118 are opened, and the call is ended. Then step 20
Return to step 1 and restart the bell incoming call monitoring.

By the way, the bell incoming monitoring of the station line 117 in step 204 is the same as the processing in step 203, and if there is a bell incoming on the station line 117, the step is taken to prevent the incoming collision.
Return to 201 and continue bell alert monitoring. If a bell incoming call is not detected on the office line 117, the process proceeds to step 205, where the relays 104 and 109 are turned on, the incoming call on the office line 118 is captured, and the outgoing call on the office line 117 is captured. Subsequent operations can be described in the same manner as in the case where the incoming call is captured on the station line 117 and the outgoing call is captured on the office line 118.

As described above, in the conventional call transfer device, a method is employed in which the DTMF signal transmitted from the caller's telephone is transmitted as it is to the call originating exchange via the call exchange and the call transfer device. I was

SUMMARY OF THE INVENTION However, in such a method, the connection inside the call transfer device is reduced due to the signal loss caused by the connection loss of the central office and the transmission loss of the commercial communication line before reaching the call transfer device. Even if the loss is 0 dB, if the distance from the caller's location to the location where the call transfer device is installed is long, the DTMF signal sent from the caller satisfies the receivable level of the central office exchange on the originating line. In some cases, the originating central office did not operate normally.

Means for Solving the Problems In order to solve the above-mentioned conventional problems, the present invention provides a tone signal receiving means for receiving a tone signal, and a tone signal for transmitting a tone signal corresponding to the signal received by the tone signal receiving means. And transmitting means for connecting the tone signal receiving means to the called-side station line, and then capturing the calling-side station line to obtain the tone signal transmitting means. The output is output to this calling line, and when it is detected that a signal indicating the end of the call has arrived from the calling line, the tone signal receiving means is disconnected from the called line. The control is performed.

According to the present invention, the tone signal newly generated in the call transfer device is transmitted to the calling line by the above-described configuration, so that connection loss of the tone signal does not occur. Also, the tone quality of the tone signal sent to the office line is improved.

Also, when a signal indicating the end of the call, such as a CPC signal, is sent from the called station line, the tone signal receiving means is disconnected so that, for example, an incoming call is sent to the called station line. Yes, then, if the line is cut off due to some kind of trouble, or if you accidentally enter the telephone number to make a call and you cut off the line, if the tone signal receiving means is no longer needed, immediately Then, the tone signal receiving means is separated from the called line.

Embodiment An embodiment of a call transfer device according to the present invention will be described below with reference to FIGS. 1, 2, and 3. FIG.

FIG. 1 is a block diagram of a call transfer device according to the present invention.
Is a call transfer device main body.

Reference numeral 303 denotes a bell detection unit which detects a bell signal transmitted from the central office exchange 316 through a central office line 317 and a capacitor 302 for blocking DC power. The detection output of the bell detection unit 303 is input to the control unit 301 and used for incoming call determination. 304
Is a relay for capturing the office line 317, which is controlled by the control unit 301 and forms / opens a DC loop with respect to the office exchange 316, and indicates the intention to respond to the call or end the call. A control unit 301 has a program area PA for storing a control program according to the flowchart of FIG. 305 is central office exchange 316
A CPC signal detection unit that detects a CPC signal transmitted through the local line 317 and notifies the control unit 301 of the CPC signal. Capacitor 306
Is for interrupting the direct current of the office line 317 and transmitting only the speech voice band signal between the office line 317 and the contact a of the relay 324 and the contact d of the relay 325. On the other hand, a capacitor 307 connected to the central office 319 through the office line 318 and a bell detection unit
308, relay 309, CPC signal detection unit 310 are respectively a capacitor 302, bell detection unit 303, relay 304, CPC signal detection unit 30
Works the same as 5. The capacitor 311 cuts off the direct current of the local line 318, and the contact b between the local line 318 and the relay 324 and the relay.
This is for transmitting only the speech voice band signal to and from the contact c of the node 325.

The DTMF signal receiving unit 327 is connected to the relay 324, and the control unit 30
By switching to contact a or b by 1
Or, it is configured to be able to receive the DTMF signal arriving from either of the office lines 318, and the received data is transmitted to the control unit 30.
Entered into 1. The relay 324 is a contact e of the relay 326.
Through the relay 325, and establishes connection between the office line 317 and the office line 318 in the speech voice band. A DTMF signal transmission unit 328 is controlled by the control unit 301 to transmit a DTMF signal having a signal code equal to the DTMF signal received by the DTMF signal reception unit 327. The output of the DTMF signal transmission unit 328 is connected to the contact f of the relay 326, and the relay 326 is connected to the contact e side by the control unit 301 so that communication can be performed between the office line 317 and the office line 318 except when transmitting the DTMF signal. It is controlled as follows.

FIG. 2 is a flowchart showing the operation of the call transfer device of the present invention. FIG. 3 is a timing chart when the DTMF signal is reproduced and relayed in the present invention.

In the flowchart of FIG. 2, in step 401, the bell detecting unit 303 determines whether or not there is a bell incoming call on the local line 317, and if there is no incoming call, executes the next step 402,
If there is, step 403 is executed. In step 402, the bell detector 308 determines whether there is a bell incoming call on the local line 318, and if there is no incoming call, returns to the first step 401 and returns to the first local line 317.
And the bell incoming call monitoring of the office line 318 is repeated. If a bell incoming call is detected in step 402, the next step 404 is executed. In step 401, a bell call is detected on the office line 317 in step 401, and when the process proceeds to step 403, it is determined whether or not there is a bell call on the office line 318 in order to capture the outgoing call on the office line 318. Make a decision. If there is a bell incoming call on the office line 318, an incoming collision occurs. Therefore, the office returns to step 401 without capturing the office line 318 and monitors the incoming call on the office line 317 and the office line 318. If there is no bell call on the office line 318, the next step is performed because the call can be captured.
406, the relay 324 is connected to the contact a side, and the relay 32
5 is connected to the contact c side. Accordingly, the DTMF receiving unit 327 is connected to the central office 317, and the DTMF transmitting unit 328 is connected to the central office 318. Next, in step 407, the relay 304 is turned on, and the station line 317
, The relay 309 is turned on, and the station line 318 is transmitted and captured. In step 408, the relay 326 is connected to the contact e side, and the dial tone transmitted from the central office 319 through the office line 318 is set to be audible on the telephone 312 of the caller.
In steps 409 and 410, step 20 in FIG.
6. In step 207, monitor the CPC signals of both office lines as already described. If no CPC signal is received in both steps,
Proceed to the next step 411, where the DTMF signal
Monitors reception of MF signals. If the DTMF signal has not been received, the process proceeds to step 414, and the relay 326 remains connected to the contact e.

Next, in step 415, the oscillation of the DTMF transmitting unit 328 is stopped, and the process returns to step 409, and if the DTMF signal is not being received, steps 409, 410, 411, 414, and 415 are repeated.

FIG. 3 is a timing chart showing the transmission timing of the DTMF signal. Here, a) shows a DTMF signal input to the DTMF signal receiving unit 327, and b) shows a DTMF signal transmitting unit 327.
DTMF signal output from the relay 326, c) shows a control signal of the relay 326, and d) shows a signal appearing at the contact g of the relay 326.

When the reception of the DTMF signal is determined in step 411, the process proceeds to step 412, where the control unit 301
DTM with signal code equal to DTMF signal received for 328
Start transmission of F signal. In this state, the relay 326 is in the contact e side connection state, and the reception DTMF signal for the time required for the DTMF signal detection passes through the local line 318 for t during the time t as shown by the relay contact g signal waveform of 514. Becomes Then, in step 413, the relay 326 is connected to the contact f. After this,
As long as the reception of the DTMF signal continues, the relay 326 remains connected to the contact f side, and the DTMF signal 507 oscillated by the DTMF signal transmission unit 328 is continuously transmitted to the central office 319 through the office line 318. You. When the process of step 413 is completed, the process returns to step 409, and steps 409, 410, 411, 412, and 413 are repeated as long as the DTMF signal is received. Next, DTMF reception ends in step 411.
When 504 is detected, the process proceeds to step 414 again, and the relay 326
Is connected to the contact e side, and the DTMF signal sent to the office line 318 is stopped. Next, at step 415, the DTMF signal transmission unit 328
508 is stopped. At this point, after a call is established with the called telephone 323, the calling telephone 312 or the called telephone 323 is called.
If either ends, step 409 or step 410
If a CPC signal is detected on the station line 317 or on the station line 318, the process proceeds to step 416 to stop the oscillation of the DTMF signal transmitting unit 328. This processing is performed when the DTMF signal transmission unit 328
It is necessary to stop the oscillation of the DTMF signal transmission unit 328 when the CPC signal detection unit (305 or 310) receives the CPC signal in 07. Then, the process proceeds to step 417, where the relays 304, 309
Is turned off, the office line 317 and the office line 318 are opened, and the call ends. Thereafter, the flow returns to step 401 to monitor the station line 317 and a new bell incoming call on the station line 318.

By the way, when a bell incoming call is detected on the station line 318 in step 402, the process proceeds to step 404, and the bell incoming call on the station line 317 is monitored. If a bell incoming call is detected, the process returns to step 401 to continue bell monitoring for both office lines in order to prevent an incoming collision between both office lines. However, if a bell call is not detected on the office line 317, the process proceeds to step 405, where the relay 324 is connected to the contact b and the relay 325 is connected to the contact d.
In this state, the DTMF signal receiving unit 327 is connected to the destination line 318, and the DTMF signal transmitting unit 328 is connected to the calling line 317. Office line
It can be described in the opposite situation where 317 is the receiving side and office line 318 is the transmitting side.

As described above, when the station line on the called side is captured as in the present embodiment, a DTMF signal arriving from this station line is received, a DTMF signal corresponding to the signal is generated, and the generated DTMF signal is generated. Is transmitted to the calling line, so that a tone signal newly generated in the call transfer device is transmitted to the calling line, and connection loss of the DTMF signal is reduced. This does not happen, and the sound quality of the DTMF signal sent to the office line is also improved.

For this reason, the sound quality is good for the central office of the calling line.
It is possible to transmit a DTMF signal irrespective of the attenuation due to connection loss, and it is possible to reliably call a target party.

In general, a call transfer device is often composed of a large number of office lines, and rather than providing a DTMF signal reception unit 327 for all the office lines, only when a DTMF signal is transmitted, the DTMF signal reception unit 327 or the DTMF signal If the transmitting unit 328 is connected, the DTMF signal receiving unit 327 and the DTMF signal transmitting unit 328 can also be used as another station line, and the DTMF signal receiving unit 327 and the DTMF signal
It is possible to reduce the number of transmission units 328 and reduce the cost. Therefore, as in the embodiment, the CP
If a signal indicating the end of the call, such as C signal, is sent, D
By disconnecting the TMF signal receiving unit 327 and the DTMF transmitting unit 328, for example, a call is received on the called line, and then the line is disconnected due to some kind of failure, or a telephone that should make a call If the DTMF signal receiving unit 327 or DTMF transmitting unit 328 becomes unnecessary, such as when the line is disconnected due to an incorrect number entry, the DTMF signal receiving unit 327 or DTMF
The transmitting unit 328 is separated from the called line, and as described above, the DTMF signal receiving unit 327 and the DTMF transmitting unit 328 can be shared by a plurality of line lines.

Further, the CPC of one of the local line CPC signal detectors 305 (310)
When a signal is detected, the relay 304 (309) of this office line is turned off.
F, and in addition to opening this station line, also turning off the relay 309 (304) of the other station line and opening this station line. Both lines,
The line is quickly opened, the time for which the line is connected is shortened, the telephone charge can be reduced, and the line can be used for other transfer operations. Effective use of lines becomes possible.

The present invention provides a tone signal receiving means for receiving a tone signal, and a tone signal transmitting means for transmitting a tone signal corresponding to the signal received by the tone signal receiving means. When the call is captured, the tone signal receiving means is connected to the called line, and then the calling line is captured, and the output of the tone signal transmitting means is output to the calling line. Further, when it is detected that a signal indicating the end of the call has arrived from the calling station line, the tone signal receiving means is controlled to be disconnected from the called station line. A tone signal newly generated in the call transfer device is sent to the office line, so that connection loss of the tone signal does not occur, and the tone quality of the tone signal sent to the office line is also improved. Good sound quality to the central office of the calling line In addition, it is possible to transmit a tone signal having no relation to attenuation due to connection loss, and it is possible to reliably call a target party.

In general, a call transfer device is often composed of a large number of office lines, and rather than providing tone signal receiving means for all the office lines, the tone signal is transmitted only when the tone signal is transmitted by the above-described transfer. If the receiving means is connected, it becomes possible to use the tone signal receiving means also as another station line, so that the number of tone signal receiving means can be reduced and the cost can be reduced. Therefore, as in the present invention, when a signal indicating the end of a call, such as a CPC signal, is transmitted from the called station line, the tone signal receiving means is disconnected, for example, If a line is received and then the line is disconnected due to some kind of trouble, or if the telephone number to be called is erroneously entered and the line is disconnected, the tone signal receiving means will be When the state becomes unnecessary, the tone signal receiving means is immediately disconnected from the called line, and as described above, a plurality of station lines can be used as the tone signal receiving means.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a call transfer device according to the present invention, FIG. 2 is a flowchart showing processing in the call transfer device according to the present invention, FIG. 3 is a timing chart of DTMF signal transmission by the call transfer device, and FIG. FIG. 1 is a configuration diagram of a conventional call transfer device, and FIG. 5 is a flowchart showing processing in the conventional call transfer device. 112,312 Telephone 113,313 Telephone line 115,315 Commercial telephone line 117,317 Telephone line 118,318 Telephone line 120,320 Commercial telephone line 122,322 Telephone line 123,323 Telephone 502 Received DTMF signal 507 Transmit DTMF signal

Claims (4)

(57) [Claims] 1. A first terminal and a second terminal connected to different office lines, respectively, first acquisition means for acquiring / opening an office line connected to the first terminal, and Second capturing means for capturing and releasing the office line connected to the second terminal, tone signal receiving means for receiving a tone signal, and tone signal for transmitting a tone signal in response to the reception of the tone signal receiving means. Sending means, an end signal detecting unit for detecting a signal indicating an end call coming from the first terminal, an incoming call is generated at the first terminal, and When the station line connected to the terminal 1 is captured,
The tone signal receiving means is connected to the first terminal, and thereafter, the second capturing means captures the office line connected to the second terminal. Secondly, control means for connecting to the terminal, wherein the control means further disconnects the tone signal receiving means from the first terminal when the end signal detection unit detects a signal indicating end of call. A call transfer device for performing control. 2. The control device according to claim 2, further comprising, when said end signal detecting unit detects a signal indicating the end of said call, controlling to disconnect said tone signal sending unit from said second terminal. The call transfer device according to claim 1. 3. A first terminal and a second terminal respectively connected to different office lines, first acquisition means for acquiring / opening the office line connected to the first terminal, and Second capturing means for capturing and releasing the office line connected to the second terminal, tone signal receiving means for receiving a tone signal, and tone signal for transmitting a tone signal in response to the reception of the tone signal receiving means. Sending means, an end signal detecting unit for detecting a signal indicating an end call coming from the first terminal, an incoming call is generated at the first terminal, and When the station line connected to the terminal 1 is captured,
The tone signal receiving means is connected to the first terminal, and thereafter, the second capturing means captures the office line connected to the second terminal. Secondly, control means for connecting to a terminal, wherein the control means further disconnects the tone signal transmitting means from the second terminal when the end signal detection unit detects a signal indicating end of call. A call transfer device for performing control. 4. A first terminal and a second terminal respectively connected to different office lines, first acquisition means for acquiring / opening an office line connected to the first terminal, and Second capturing means for capturing and releasing the office line connected to the second terminal, tone signal receiving means for receiving a tone signal, and tone signal for transmitting a tone signal in response to the reception of the tone signal receiving means. Sending means, an end signal detecting unit for detecting a signal indicating an end call coming from the first terminal, an incoming call is generated at the first terminal, and When the station line connected to the terminal 1 is captured,
The tone signal receiving means is connected to the first terminal, and thereafter, the second capturing means captures the office line connected to the second terminal. Secondly, control means for connecting to a terminal, the control means further comprising, when the end signal detection unit detects a signal indicating end of call, a station line connected to the first terminal, A call transfer device for performing control for opening a line connected to a second terminal.