JP2509527Y2 - Fax machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Use The present invention relates to a facsimile machine.

(B) Conventional technology In a recent facsimile machine, after detecting an incoming call, the line is captured, and then a 1100 Hz CNG signal indicating that the terminal is a facsimile terminal is detected from the calling side.
If the CNG signal cannot be detected within a predetermined time, it is determined that the call is not for facsimile communication but for call purposes, and the telephone is switched to the one that is built in or attached to the facsimile machine (for example, Japanese Patent Publication No.
2-38035 gazette).

In such a facsimile machine, the transmission of the ringback tone from the exchange to the calling side is stopped when the facsimile machine seizes the line in response to the incoming call. Even when the telephone was ringing, the caller was put in a silent state and did not know what the receiver was doing. Therefore, when the line is captured, the facsimile machine generates a ringback tone and sends it to the calling side.

(C) Problems to be Solved by the Invention In order to generate a ring back tone in a conventional facsimile apparatus, firstly, a 400 Hz rectangular wave generated by a rectangular wave generating circuit is turned on every 1/32 seconds, Repeatedly turning off and then turning on for 1 second and 2 seconds, after passing through a gate, a method of removing harmonic components by a filter. Second, DTMF (dual frequency generation circuit) signal generation provided in the modem circuit built into the facsimile machine. 1/32 of 400Hz tone signal from circuit
A method of repeating on and off every second is adopted, and it is configured to generate a tone signal similar to a ringback tone obtained by AM-modulating the 400Hz tone signal generated by the exchange at 16Hz.

However, in the first method, it is necessary to separately provide a circuit for generating a ring back tone, which causes an increase in cost, and in the second method, the signal level changes abruptly when switching every 1/32 seconds. There was a problem that there was no noise and the ring back tone was unnatural and difficult to hear.

(D) Means for Solving the Problems The present invention has been made to solve the above problems.
The DTMF signal generation circuit of the modem circuit is configured by means for controlling so as to simultaneously generate two frequencies of 400 Hz and 416 Hz, synthesize them, and output them.

(E) Operation Since the present invention is configured as described above, it is possible to generate a tone signal close to the ringback tone of the exchange without adding a separate circuit.

(F) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

(1) is a well-known transmission / reception circuit including a reading circuit for reading a transmission original and a recording circuit for receiving and recording, and is controlled by the control circuit (2). The control circuit (2) is composed of a microprocessor and controls each part based on a built-in processing program. (3) is a keyboard equipped with a communication key, a copy key, a numeric keypad, and various function keys, and outputs a key signal to the control circuit (2).
(4) is a modem circuit connected to the transceiver circuit (1),
A modulation / demodulation circuit (5) for modulating a transmission signal and demodulating a reception signal as shown in FIG. 2, and a DTMF for generating a dual frequency signal.
It is composed of a signal generation circuit (6) and is controlled by a control circuit (2). In the DTMF signal generating circuit (6), the tone frequency generated under the control of the control circuit (2) can be arbitrarily set.

A line switching circuit (7) appropriately switches the telephone line (L) between the modem circuit (4) and the telephone (8), and the switching is performed under the control of the control circuit (2). Reference numeral (9) is an incoming call detection circuit which is connected to the telephone line (L) and detects an incoming bell signal, and outputs a detection output to the control circuit (2).
Reference numeral (10) is a hook detection circuit for detecting an off-hook of the telephone (8), which outputs a detection output to the control circuit (2).
Reference numeral (11) is a speaker driven by a call signal from the control circuit (2) when making a telephone call.

 Next, the operation of the present invention having such a configuration will be described.

First, in the standby state, the control circuit (2) detects whether or not there is an incoming call by checking the output of the incoming call detection circuit (9) in step (S1). If there is an incoming call and the incoming call is detected by the output of the incoming call detection circuit (9), the process proceeds to step (S2) and the line switching circuit (7) is controlled to switch the telephone line (L) to the modem circuit (4) side to capture the line. To do. Then, the control circuit (2) proceeds to step (S3) to generate a CED signal and send it to the telephone line (L) through the modem circuit (4) to inform the calling side that the response has been made. When the CED signal is transmitted, the control circuit (2) proceeds to step (S4) to detect whether or not the CNG signal is transmitted from the transmitting side.

At this time, if the sender is a facsimile machine, CN
Since the G signal is transmitted, when the CNG signal is detected, the process proceeds to step (S5) to exchange a predetermined control signal between the facsimile devices, and then the received signal is processed in step (S6), and then step (S7). Receive recording with. And the control circuit (2) that detected the end of all reception in step (S8)
Controls the line switching circuit (7) in step (S9) and switches the switch to the telephone (8) to disconnect the line and return to the standby state.

On the other hand, when the caller is not a facsimile machine but a telephone for the purpose of making a call, the control circuit (2) advances from step (S4) to step (S10) because there is no CNG signal transmission After detection, step (S
At 11), a signal for calling is generated and a speaker (11) is driven to make a telephone call. At the same time, the control circuit (2) controls the DTMF signal generating circuit (6) of the modem circuit (4) in step (S12) to generate tone signals of 400 Hz and 416 Hz. The generated tone signal is synthesized in the DTMF signal generation circuit (6) and is transmitted to the telephone line (L) via the line switching circuit (7) as a signal accompanied by a level change of a cycle of 1/16 second due to a beat. It is sent out and transmitted to the originating side. This signal is a signal that approximates the ringback tone generated by the exchange, and the caller knows that the called party is ringing. The generated ringback tone signal is step (S1
3) It is controlled by (S14) to generate for 1 second and pause for 2 seconds. The telephone ringing control circuit (2) detects whether or not the telephone (8) is off-hook by checking the output of the hook detection circuit (10) at step (S15). If it is detected, the process proceeds to step (S16) to stop the driving of the speaker (11) to stop the telephone call, and at the same time, stop the driving of the DTMF signal generating circuit (6) to stop the generation of the ringback tone. Then, in step (S17), the line switching circuit (7) is controlled to switch the switch to the telephone (8) side. This allows a call with the caller.

The DTMF signal generation circuit (6) of the modem circuit (4) is controlled under the control of the control circuit (2) when the telephone number data to be dialed by the ten keys of the keyboard (3) is input for transmission. DTMF signal is generated and a tone dial signal is output to the telephone line (L).

(G) Effect of the invention As described above, the facsimile apparatus of the invention is configured so that the DTMF signal generating circuit of the modem circuit generates the signals of 400 Hz and 416 Hz and uses the combined output signal as a ring back tone. It is possible to generate a clean signal having a sound quality close to that of the ring back tone signal generated, and it is extremely effective in practical use.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the facsimile apparatus of the present invention, FIG. 2 is a block diagram showing the configuration of the modem circuit of FIG. 1, and FIG. 3 is a flow chart showing the operating state of FIG. (1) ... Transmitting / receiving circuit, (2) ... Control circuit, (4) ...
… Modem circuit, (6) …… DTMF signal generation circuit, (7)…
… Line switching circuit.

Claims (1)

(57) [Scope of utility model registration request] 1. A control means and a DTMF signal generation circuit capable of synthesizing and outputting two signals having different frequencies under the control of the control means, wherein the control means controls the DTMF signal generation circuit. A facsimile machine characterized by transmitting a composite signal of 400 Hz and 416 Hz output from the DTMF signal generating circuit to a telephone line as a ring back tone at predetermined intervals.