JPH0243866A - Call transfer device - Google Patents

Abstract

PURPOSE:To surely control a caller side station exchange by receiving a signal sent from a telephone set at the incoming side trunk line by a signal receiver and sending a signal having the same data as the received signal from a signal generating means. CONSTITUTION:A multi-frequency selection signal (DTMF signal) coming from the incoming trunk line is received by a signal reception means 327 and a signal generating means 328 sends the DTMF signal equal to the received signal code. Thus, the DTMF signal is sent to a caller trunk line of the device without being affected by a signal level attenuation or the like through a relay station exchange and a commercial communication line caused from the location of the caller till the call transfer device installing location and the call transfer device with high reliability is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a method for transmitting a DTMF signal to a central office exchange on the originating and capturing side using a multi-frequency selection selection signal (hereinafter referred to as DTMF signal) transmitted from a calling party's telephone. The present invention relates to a call transfer device that selects a calling party.

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

Reference numeral 103 denotes a bell detection section, which detects a bell signal sent from the central office exchange 116 through the central office line 117 and the capacitor 102 for cutting off DC current. The detection output of the bell detection section 103 is input to the control section 101 and used for determining incoming call. Reference numeral 104 denotes a relay for capturing the central office line 117, which is controlled by the control unit 101 to form/open a DC loop to the central office exchange 116, and to indicate the intention to make a call, answer, or end a call. 105 is the central office line 1 from the central office exchange 116.
This is a CPC signal detection unit that detects an instantaneous interruption of the DC loop current (hereinafter, this instantaneous interruption of the DC loop current will be referred to as a CPC signal), which means the end signal sent out through the CPC signal 17, and notifies the control unit 101 of the instantaneous interruption. The capacitor 106 is used to cut off direct current from the office line 117 and transmit only the voice band signal to the internal communication path 124. On the other hand, a capacitor lO7, a bell detection section 108, a relay 109, a CPC signal detection section 110, a capacitor 111 connected to the office line 118
are a capacitor 102, a bell detection section 103, a relay 104, a CPC signal detection section 105, and a capacitor 10, respectively.
Performs the same function as 6.

Internal communication path 124 connects capacitor 106 and capacitor 1.
11, and performs a signal connection in the speech voice band between the office line 117 and the office line 118.

Telephone 112 is a telephone under the control of central office exchange 114 and is connected via central office line 113. 115 is a commercial communication line, which is specified here as connecting between the central office exchange 114 and the central office exchange 116. Telephone 123, office line 1
22. The functions of the exchange 121 and the commercial communication line 120 are the same as those of the telephone 112, the central office line 113, the exchange 114, and the commercial communication line 115.

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

The operation will be explained below using the flowchart shown in FIG. In step 201, station 1 is detected by bell detection 81O3.
It is determined whether or not there is an incoming call at 117, and if there is no incoming call, execute the next step 202, and if there is, step 2
Execute 03. In step 202, the bell detection unit 108
It is determined whether or not there is an incoming bell call on the central office line 118, and if there is no incoming call, the process returns to the first step 201 and returns to the central office line 11.
7 and office line 118 are repeated. Further, when an incoming call is detected in step 202, the next step 204 is executed. If an incoming bell call is detected on the office line 117 in the previous step 201 and the process moves to step 203, in order to capture the call on the office line 118 side,
It is determined whether there is an incoming call on the side. If there is an incoming bell call on the office line 118, a collision will occur, so the office line 118
The process returns to step 201 without capturing the station line 117 and station line 1.
Monitors 18 incoming calls. If there is no incoming call on the office line 118, the call can be captured, so the process moves to the next step 205, where the relays 104 and 109 are turned ONL, the incoming call is captured on the office line 117, and the call on the office line 118 is captured. In this state, the caller connects the telephone 112 to the central office line 113, central office exchange 114,
This means that a new call can be made to the central office line 118 via the commercial communication line 115, central office exchange 116, and central office line 117. The outgoing operation is a DTM sent from the telephone 112.
The F signal connects the office line 113, the office exchange 114, the commercial communication line 115, the office exchange 116, the office line 117, and the relay 104.
, capacitor 106, internal communication path 124, capacitor 1
11, relay 109, central office switch 11 via central line 118
9 can be controlled. Here, the central office exchange 119 analyzes the DTMF signal transmitted from the telephone 112, and selects the central exchange 121 via the commercial communication line 120 in order to have the call arrive at the telephone 123 desired by the caller.
The system instructs the type exchange 121 to send a bell signal to the central office line 122 to which the telephone 123 is connected. For calls, use telephone 12
The call is confirmed when the called party No. 3 picks up the receiver. The end of the call is confirmed when the user of telephone 112 or telephone 123 puts the handset back on, and the central office exchange (116 or 119) on the side that put the handset back on sends a C to the call transfer device.
A PC signal is sent out. Step 206 and Step 2
07 is a process in which the CPC signal of each office line is detected by the CPC signal detection unit (105 or 110).
Step 206 and Step 207 until the C signal is detected.
Repeat. When a CPC signal is detected in one of these steps, the process moves to step 208, and the relay 104.109
to 0FFL, open the central office line 117 and the central office line 118, and end the call. Thereafter, the process returns to step 201 and the incoming bell monitoring is restarted.

By the way, the monitoring of incoming bell calls on the office line 117 in step 204 is the same as the process in step 203, and if there is an incoming bell call on the office line 117, collision of incoming calls should be prevented (return to step 201 to continue monitoring incoming bell calls). If no incoming bell call is detected on the office line 117, the process moves to step 205, and the relays 104 and 109 are turned ON.
, the incoming call is captured on the office line 118, and the outgoing call is captured on the office line 117. The subsequent operations can be explained in the same way as in the case where incoming calls are captured on the office line 117 and outgoing calls are captured on the office line 118 from the opposite standpoint.

As explained above, in the conventional call transfer device, the DTMF signal transmitted from the calling party's telephone is sent directly to the originating side exchange via the terminating side exchange and the call transfer device. was taken.

Problems to be Solved by the Invention However, in such a method, the connection within the call transfer device is reduced due to a reduction in the signal level due to connection loss of the numerous central office exchanges and transmission loss of the commercial communication line before reaching the call transfer device. Even if the loss is OdB, if the distance from the caller's location to the place where the call forwarding device is installed is long, the DTMF signal sent by the caller will satisfy the level that can be received by the central office exchange on the calling side's central office line. In order to solve the above-mentioned problems, the present invention receives a signal transmitted from a telephone on the receiving side line by a signal receiver, and receives a signal having the same data as the received signal. is transmitted by a signal generating means.

Effect: With the above configuration, the signal generating means can generate a DTMF signal having the same signal code as the received signal even if the signal level decreases due to the connection loss of the numerous central office exchanges and the transmission loss of the commercial communication line before reaching the call transfer device. By sending the information from the transmitter, it is possible to reliably control the originating exchange.

Embodiment Hereinafter, an embodiment of the call transfer device according to the present invention will be described using FIG. 1, FIG. 2, and FIG. 3.

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

Reference numeral 303 denotes a bell detection section, which detects a bell signal sent from the central office exchange 316 through the central office line 317 and the capacitor 302 for cutting off DC current. The detection output of this bell detection section 303 is input to the control section 301 and used for determining incoming call. 304 is a relay for capturing the station n317, which is controlled by the control unit 301, forms/opens a DC loop with the central office exchange 316, and indicates an intention to respond to a call or end a call. A control unit 301 has a program area PA for storing a control program according to the flowchart shown in FIG. 305 is the central office line 31 from the central office exchange 316
7 and detects the CPC signal sent through the control unit 30.
This is a CPC signal detection unit that notifies the CPC signal to the CPC signal. capacitor 30
6 cuts off the direct current of the central line 317 and connects the central line 317 and relay 3.
24 and contact d of the relay 325 to transmit only voice band signals. On the other hand, a capacitor 307, a bell detection section 308, a relay 309, and a CPC signal detection section 310 connected to the central office exchange 319 through a central office line 318 are equivalent to a capacitor 302, a bell detection section 303, a relay 304, and a CPC signal detection section 305, respectively. perform the functions of Also, the capacitor 311 is connected to the central line 318.
This is to cut off the direct current of the line 318 and the contact point C of the relay 324 and the contact point C of the loop 325 to transmit only the speech voice band signal.

DTMF signal receiving section 327 is connected to relay 324,
It is configured so that it can receive the DTMF signal coming from either the office line 317 or the office line 318 by switching to contact a or b by the control unit 301.
Received data is input to control section 301. Further, the relay 324 is connected to the relay 325 through the contact e of the relay 326, and connects the central office line 317 and the central office line 318 in the speech voice band. 328 is a DTMF signal sending unit;
The control unit 301 controls the DTMF signal receiving unit 327 to send out a DTMF signal having the same signal code as the DTMF signal received by the DTMF signal receiving unit 327 .

The output of the DTMF signal sending unit 328 is connected to the contact f of the relay 326, and the relay 326 is controlled by the control unit 301 to
When the MF signal transmission signal is sent out, control is performed so that the connection between the outside station 317 and the central office line 318 is made to the contact e side so that communication is possible.

FIG. 2 is a flowchart showing the operation of the call transfer device of the present invention. FIG. 3 is a timing chart for reproducing and repeating a DTMF signal according to the present invention.

In the flowchart of FIG. 2, in step 401, the bell detection unit 303 determines whether or not there is an incoming call on the central office line 317. If there is no incoming call, the next step 402 is executed, and if there is, step 403 is executed. . Step 4
In step 02, the bell detector 308 determines whether or not there is an incoming call on the office line 318. If there is no incoming call, the process returns to the first step 401 and the monitoring of incoming bell calls on the office line 317 and 318 is repeated. Further, if an incoming call is detected in step 402, the next step 404 is executed. Where,
If an incoming bell call is detected on the office line 317 in the previous step 401 and the process moves to step 403, it is determined whether there is an incoming bell call on the office line 318 side in order to capture the outgoing call on the office line 318 side. . If there is an incoming bell call on the office line 318, an incoming call collision will occur, so the process returns to step 401 without capturing the office line 318 and monitors the incoming bell call on the office line 317 and 318.

If there is no incoming bell call on the office line 318, the call can be captured, so the process moves to the next step 406, and the relay 324 is connected to contact a.
Connect the relay 325 to the contact C side. As a result, the DTMF receiving section 327 is connected to the office line 317 side, and the DTMF transmitting section 328 is connected to the office line 318 side.

Next, in step 407, relay 304 is turned ONL, central line 3
17 is captured, relay 309 is ONL, and central line 318 is connected.
to transmit and capture. In step 408, the relay 326 is connected to the contact e side, and the dial tone sent from the central office exchange 319 through the central office line 318 is set to be audible on the caller's telephone 312. In step 409 and step 410, step 206 and step 207 in FIG.
As mentioned above, the CPC signals of both station lines are monitored. If the CPC signal is not received in both steps, the process moves to the next step 411, and the DTMF signal receiving unit 327 receives the D
Monitors reception of TMF signals. If the DTMF signal is not received, the process moves to step 414 and the relay 326 is kept connected to the contact e side.

Next, in step 415, the oscillation of the DTMF transmitter 328 is kept stopped, and the process returns to step 409, where the DTMF
If the signal is not being received, step 409, step 41
0, step 411, step 414 and step 41
Repeat step 5.

FIG. 3 is a timing chart showing the sending timing of the DTMF signal. Here, a> indicates the DTMF signal input to the DTMF signal receiving section 327, and b) indicates the DTM
A DTMF signal output from the F signal sending unit 327 is shown, C) shows a control signal of the relay 326, and d) shows a signal appearing at the contact g of the relay 326.

By the way, when the reception of the DTMF signal is confirmed in step 411, the process moves to step 412, and the control unit 301 receives the DTMF signal.
The MF signal transmitter 328 is activated to transmit a DTMF signal having the same signal code as the received DTMF signal.

In this state, the relay 326 is in the contact e side connected state, and the reception DTMF signal is received for the time required to detect the DTMF signal.
As shown in the relay contact g signal waveform of F' double signal 514, t
It will pass to the opening line 318 side. After that, in step 413, the relay 326 is connected to the contact f side. After this, as long as the reception of DTMF signals continues, relay 326
remains connected to the contact f side, and the DTMF signal 507 oscillated by the DTMF signal transmitter 328 is continuously sent to the central office exchange 319 through the central office line 318. After completing the process of step 413, step 40
Returning to step 9, as long as the DTMF signal is received, step 409;
Steps 410, 411, 412, and 413 are repeated. Next, in step 411, the DTM
When the end of F reception 504 is detected, the process returns to step 414, where the relay 326 is connected to the contact e side and the DTMF signal sent to the office line 318 is stopped. Next, in step 415, the oscillation of the DTMF signal transmitter 328 is stopped 50.
Make it 8. After the call is established with the called telephone 323, if either the calling party telephone 312 or the called telephone 323 ends the call, step 409 or step 41 is performed.
When a CPC signal is detected on the office line 317 or 318 at 0, the process moves to step 416, and the oscillation of the DTMF signal transmitter 328 is stopped. This processing is necessary in order to stop the oscillation of the DTMF signal transmitting section 328 when the CPC signal detecting section (305 or 310) receives a CPC signal while the DTMF signal transmitting section 328 is generating the DTMF signal 507. After that, the process moves to step 417, and the relay 30
4. Set 309 to 0FFL, open office line 317 and office line 318, and end the call. After that, the process returns to step 401, and the station line 3
17 and central office line 318.

By the way, if an incoming bell call on the office line 318 is detected in step 402, the process moves to step 404, and the incoming call on the office line 317 is monitored. If an incoming bell call is detected, the process returns to step 401 to continue monitoring the bells of both office lines in order to prevent a collision of incoming calls on both office lines. However, if no incoming call is detected on the office line 317, the process moves to step 405, where the relay 324 is connected to the contact side and the relay 325 is connected to the contact d side. In this state, the DTMF signal receiving section 327 is connected to the receiving side's office line 318, and the DTMF signal transmitting section 328 is connected to the calling side's office line 317. This can be explained from the opposite standpoint, where the office line 317 is on the receiving side and the office line 318 is on the calling side.

Effects of the Invention The present invention receives a DTMF signal arriving from the terminating station line side by a signal receiving means, and converts it into a DMF signal that is equivalent to the received signal code.
Since the TMF signal is transmitted from the signal generating means, the transmission line of the device is not affected by signal level attenuation caused by relay exchanges and commercial communication lines that occur between the caller's location and the location where the call transfer device is installed. It is possible to transmit a DTMF signal to the other side, which has the effect of providing a highly reliable call transfer device.

[Brief explanation of the drawing]

FIG. 1 is a block 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. This figure is a block diagram of a conventional call transfer device, and FIG. 5 is a flowchart showing processing in the conventional call transfer device. 112.312 113.313 115.315 117.31? 118.318 120.320 122.322 123.323 502 ・ ・ ・ ・ 507 ・ ・ ・ ・ Telephone office line Commercial communication line Office line Office line Commercial communication line Office line Telephone reception DTMF signal transmission DTMF signal

Claims (1)

[Scope of Claims] Signal receiving means for receiving a multi-frequency selection selection signal arriving at a first terminal; and a multi-frequency selection selection signal having a code equal to the code of the multi-frequency selection selection signal received by the signal receiving means. A call transfer device comprising: a signal generating means for generating a multi-frequency selection selection signal generated by the signal generating means; and a sending means for sending a multi-frequency selection selection signal generated by the signal generating means to a second terminal.