JPS60200677A - Telephone set circuit having holding tone sending function - Google Patents

Abstract

PURPOSE:To reduce the quantity of hardware and to reduce power consumption of a holding circuit by using a sending amplifier, speaker amplifier etc. used as a speech circuit also as an amplifier circuit of a holding tone signal. CONSTITUTION:At the time of talking by a handset, switches 30, 31 are connected to (a) side respectively, and a switch 34 is made non-conductive. In case of handset speaker talking, a switch 33 is in conduction in addition to the above. When holding, switches 30, 31 are connected to b side respectively. Accordingly, by using a sending preamplifier 2, a sending main amplifier 3 and a speaker amplifier 6 used as a talking circuit 1 in common for sending a holding tone, which required newly as a holding circuit 17 are a holding tone generting circuit 26, buffer circuits 27, 28 and switching devices 30, 31 which are low in power consumption and small in hardware and a power source circuit 29 with small current capacity, and a power amplifier and a power source circuit with large current capacity are made unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a circuit configuration of a telephone circuit having a holding music sending function, which has a small amount of /- cards, is inexpensive, and requires a small mounting volume.

(Prior art) While making handset calls (calls using a transmitter and handset), handset loudspeaker calls (), and handset calls,
The communication circuit of an electronic telephone that realizes the function of monitoring and listening to the contents of incoming calls through a speaker is generally constructed as shown in FIG. Reference numeral 1 denotes a communication circuit, and 1), la, and lb are current supply terminals of the communication circuit, as well as input/output terminals for transmitting and receiving alternating current signals. Here, the terminal 1b is shown as a common grounding point for each circuit (substrate of an IC circuit). 2 is a transmitting preamplifier, 3 is a transmitting main amplifier, 4 is a receiving preamplifier, 5 is a receiving main amplifier, and 6 is a speaker amplifier. 7 is an audio switch control circuit, which includes an amplifier 7a that amplifies the output signal of the transmitting preamplifier 2;
A circuit 7bs for rectifying and smoothing the output detects the rectified and smoothed transmitting signal level, and if it is higher than the specified value, stops the operation of the transmitting system loss circuit 8 of the audio switch and operates the speaker system loss circuit 9. If the value is smaller than the specified value, send it. 1
0 is a resistor hybrid circuit for suppressing the sidetone signal of the transmitting voice, and 11 is a balance circuit network for balancing with the line impedance.

Reference numeral 12 denotes a power supply circuit for each of the circuits, which supplies a stabilized DC voltage according to the required voltage conditions of each circuit. configured.

12e and 12f indicate output terminals of the power supply circuit. 1
3 is a transmitter, 14 is a receiver, 15 is a speaker, and 1
Reference numeral 6 denotes a switch that turns off the speaker output when the telephone is in use and the speaker 15 is not listening.

Recently, these circuits have been realized as a communication circuit IC housed in a single IC, and the terminals of each circuit are exposed to an external bin of the IC as necessary.

On the other hand, the hold music sending function allows you to temporarily interrupt a call.
This function not only sends the hold tone to the other party's phone (send hold tone to the line side), but also sends the hold tone to your own phone (Hold tone monitor), and audibly displays that the line is on hold. . Here, the music on hold monitor is generally configured to output the music on hold from a speaker so that the user can hear the music on hold even when the handset is put down.

Also, while on hold, you are prohibited from sending your own outgoing signal and from listening to the other party's outgoing signal (i.e., the incoming signal from your own phone). Generally, private conversations are prevented from being overheard through the other party's telephone.

- Conventional telephone circuits are equipped with circuits that ■ send hold music to the line side, ■ send hold music to the speaker as a hold music monitor, and ■ prohibit sending and receiving calls while on hold. , a circuit as shown in FIG. 2 was used.

In Figure 2, 1 is the telephone call circuit, la and lb are the person's
It is an output terminal, and 17 is a holding circuit.

Reference numeral 18 designates a held music generating circuit, 19 an output amplifier for sending the held music to the line side, and 20 a transformer for sending only the AC signal of the held music to the line side. Reference numeral 21 indicates a speaker amplifier for transmitting the held music to the speaker, and 22 indicates a speaker. Further, 23 is a power source for the reservation circuit 17, and a partial power source or a battery is used. 24 is a switch for switching between the call circuit 1 and the holding circuit 17 and connecting it to the line side.

In this way, the hold circuit 1 is installed as a separate circuit from the call circuit.
7, the power amplifier shown in output amplifier 19° speaker amplifier f2z is required, and a large power supply capacity is required to operate them, so... This resulted in an increase in costs and an increase in costs.

(Object of the Invention) The object of the present invention is to eliminate such conventional drawbacks, and to provide a telephone circuit with a hold tone sending function that reduces the amount of hardware and the power consumption of the hold circuit. That's true.

(Structure of the Invention) According to the present invention, a transmitting amplifier, a speaker amplifier, etc., which are used as a communication circuit for the above purpose, can also be used as a circuit for amplifying a held music signal.

(Example) An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a block diagram showing an embodiment of a telephone circuit with a hold tone sending function according to the present invention. In the figure, the same functional parts as in Figure 1 are given the same reference numerals. In the figure, 25 is a hold sound source circuit, and 26 is a hold sound generation circuit composed of a melody IC and the like.

Reference numerals 27 and 28 designate buffer circuits of the held music generating circuit 2G, which perform impedance matching with the transmitting preamplifier 2 and the speaker anzoro, or set the level of the held music signal. 29 is a power supply circuit for the hold sound source circuit 25;
Hold sound source circuit 2 by stabilizing the power of the DC supplied from the station
This is for supplying power to 5. 30 is a first switch for connecting the transmitter 13 during a call, and the output terminal of the buffer circuit 27 of the hold sound source circuit 25 when on hold, to the input terminal of the transmitting preamplifier 2; This is a second switch for connecting the output terminal of the speaker system loss circuit 9 and the output terminal of the P/F circuit 28 of the reserved sound source circuit 25 to the input terminal of the speaker amplifier 6 when it is still on hold.

Reference numeral 32 indicates a switch that is open during a call and conductive when the call is on hold. Note that this switch 32 may be omitted if the power consumption of the hold sound source circuit 25 is large enough not to affect the operation of the call circuit. 33 is speaker 1
This switch is conductive even when the telephone number 5 is used to make a call and when the telephone is on hold. Reference numeral 34 shows an example of a switch for transmitting the output of the receiver main amplifier 5 to the receiver 4 during a call and prohibiting the output of the receiver main amplifier 5 from being transmitted to the receiver 14 when on hold. It may be a switch that enables/stops the operation of the receiver f5 or a switch that connects/disconnects the output terminal of the receiver main amplifier 5 and the receiver 14.

Next, an outline of the operation of this embodiment will be described. During a handset call, the switches 3o and sl are each connected to the a side, and the switch 34 is non-conducting. Therefore, the transmitting signal is sent to the line side via the transmitter 13 → the transmitting Grian f2 → the transmitting main amplifier 3 → the hybrid circuit 10 (the transmitting system loss circuit 8 does not operate during transmitting), and the receiving signal is received by the telephone receiver 14 via the high-frequency circuit 10→receiving preamplifier f4→receiving main amplifier 5. ...In addition to the above, during a loudspeaker call, the switch 33 is conductive, so the call is received from the speaker 15 via the hybrid circuit 10 → receiving preamplifier 4 → speaker amplifier f6 (speaker system loss circuit 9 does not operate when receiving a call) The signal is heard. When on hold,
Switch 3θ.

3 are each connected to the b side, and switches 32, 33゜34
becomes conductive. Therefore, power is supplied to the held sound source circuit 25, and the output signal of the held sound generation circuit 26 is transmitted from the buffer circuit 27 to the transmitting preamplifier 2 to the transmitting main amplifier 3 to the high noise loop circuit 10 (the transmitting system loss circuit 8 is the voice switch control circuit). 7, the hold tone signal is regarded as a transmission signal and is controlled so as not to operate), and then sent to the track side. Further, the output of the held tone generation circuit 26 is output from the buffer circuit 2.
8→The signal passes through the speaker amplifier 6 and is heard from the speaker amplifier 5. On the other hand, when receiving a call on hold, the hybrid circuit l
O → input to the receiver main antenna 5 via the receiver preamplifier 7″4, but since the switch 34 is conductive, the receiver 1
It will not be heard from 4 onwards. It's a trench, switch 3 is b
Since the sound is connected to the side, the sound is heard through the speaker 15. Note that since the switch 3θ is connected to the b side, it goes without saying that no transmitting signal is sent out.

In this way, in order to send out the hold music to the line side and the speaker 15, by sharing the sending preamplifier 2 and the sending main amplifier f3° speaker amplifier 6 used as the calling circuit 1, the hold sound can be transmitted to the line side and the speaker 15. What is newly required is a hold music generation circuit 26 with low power consumption and a small amount of sound.
, buffer circuit 27.2B, switch means, 30 , .
The power supply circuit 29 has a small current capacity of 3 J, and there is no need to provide a power supply circuit with a large current capacity.

Furthermore, if a CMO5 Mello Guy IC or the like is used for the hold sound generation circuit 26, the hold sound source circuit 25 can be realized with extremely low power consumption, so the power supply circuit 29 is deleted and the power supply circuit 12 of the call circuit is used as the power supply for the hold sound source circuit. It is also possible to share them.

Next, FIG. 4 shows another embodiment of the present invention. In the figure, the same functional parts as in FIG. 3 are given the same reference numerals. In the figure, numeral 35 indicates a switch which is non-conductive during a call and conductive when on hold, and may be constructed of an electronic switch such as a transistor. This switch 35 is inserted between one of the output terminals 12e of the power supply circuit 12 of the telephone call circuit 1 and the power supply terminal of the hold sound source circuit 25, and when on hold, the power supply circuit 1 of the call circuit 1
It functions to supply a part of the output of 2 to the hold sound source circuit 25.

36 is a DC voltage supply circuit which supplies the DC voltage obtained when the switch 35 is turned on to the rectifying and smoothing circuit of the audio switch control circuit 7. The output end of b, that is, the transmitting signal detecting section 7c
It is supplied to the input terminal of the circuit, and is composed of a current backflow prevention diode D1 and a current limiting resistor R4. The circuit 36 that supplies DC voltage during this hold period functions as follows.

As described above, when the music is on hold, the held tone is input from the P/F circuit 27 to the transmitting preamplifier 2, power amplified by the transmitting main amplifier 3, and sent to the line side. At this time, the voice switch control circuit 7 regards the held tone signal as a transmitting signal, and the operation of the transmitting system loss circuit 8 is stopped, and the speaker system loss circuit 9
Since the on-hold tone signal is controlled to operate, it does not occur that the hold tone signal is attenuated in the transmission system loss circuit 8 and not transmitted to the line side. However, since the melody normally used as a hold tone has a large or small amplitude and has a pause period, the transmission system loss circuit 8 operates during periods when the amplitude of the melody is small and during periods when the melody is paused. It turns out. Therefore, each loss circuit 8 of the ζ voice switch control circuit 7
, 9 may deteriorate the sound quality of the hold tone.

Therefore, when on hold, a DC voltage is always applied to the transmitting signal detecting section 7c to prevent the transmitting system loss circuit 8 from operating even during the pause period of the melody, thereby preventing deterioration of the sound quality of the held sound. be.

By inputting the output of the hold tone generation circuit 26 to the transmitter amplifier 2 and speaker amplifier 06 of the call circuit 1 in the hold state, it is possible to replace the power amplifier, etc., which requires a large amount of node and power consumption. It is possible to send the hold music to the track side and the speaker 15 without adding it. Furthermore, when on hold, the transmitter 13 is not connected to the transmitter preamplifier 2, and the output of the receiver main amplifier 5 is not transmitted to the handset 4, so the transmitter/receiver function is stopped when on hold. There is.

Furthermore, since a voice amplifier is not required, the hold sound source circuit 25 can be realized with low power consumption, and the speech circuit power supply circuit 12 can be shared as a power source for the hold sound source circuit. this is,
This means that the hold music sending function is realized only with the power supplied from the station. Furthermore, it is also possible to prevent the sound quality of the held tone from deteriorating by fixing the operation of the audio switch circuit during hold (only the speaker system loss circuit always operates).

(Effect of the invention) 1.11-Tonjiji Misaki 1F uBFII + l et al. By using the Rege call circuit as part of the hold circuit according to the present invention, the amount of cable is small and it can be implemented at low cost. This has the effect of realizing a telephone circuit with a hold tone sending function that has a small volume.

[Brief explanation of drawings]

Figure 1 is a professional configuration diagram of an electronic communication circuit;
The figure is a block diagram of a conventional telephone circuit with a hold tone sending function, and FIGS. 3 and 4 are block diagrams showing embodiments of the telephone circuit with a hold tone sending function of the present invention. 1... Call circuit, Iarlb... Input/output terminal of the call circuit, 2... Sending preamplifier, 3... Sending main amplifier, 4... Receiving amplifier, 5... Receiving main amplifier, 6... Subika angle, 7... Audio switch control circuit, 7a... Amplifier, 7b... Rectification/smoothing circuit, 7c... Transmission signal detection and loss control circuit, 8...
・Transmission system loss circuit, 9...Speaker system loss circuit, 10
... Resistance hybrid circuit, 1. ... Balanced circuit network,
12... Power supply circuit for communication circuit, 12a, 12b...
Constant current circuit, 12c, 12d constant voltage circuit, I
2 e, 12f... Output terminal of power supply circuit for telephone call circuit, 13... Transmitter, 14... Receiver, 15.22
...Speaker, 16°24.30,31,32,33
, 34.35...Switch means, 17...Holding circuit,
IFI, 26... Hold tone generation circuit '1 19.21...
Power amplifier, 2θ...Transformer, 23...External power supply, 26...Holding sound source circuit, 27.28...Buffer circuit, 29...Holding sound source power supply circuit, 36...DC voltage supply circuit . Patent applicant Nippon Telegraph and Telephone Public Corporation Iwasaki Tsushinki Co., Ltd. Figure 1 Figure 2 Figure 1ρ

Claims (3)

[Claims] (1) The output of the transmitting preamplifier is input to the transmitting main amplifier via the transmitting system loss circuit of the audio switch, and the output of the receiving preamplifier is input to the speaker amplifier via the receiving main amplifier and the speaker system loss circuit of the audio switch. A telephone set comprising a circuit configured to receive input, an audio switch control circuit that detects the presence or absence of a transmitting signal and controls the operation of the transmitting system loss circuit and the speaker system loss circuit, and a power supply circuit for each of the circuits. a first switching means that connects a transmitter to an input terminal of the transmitting preamplifier when a call is made to the hold sound source circuit in the call circuit, and connects a first output terminal of the hold sound source circuit when the call is on hold;
During a call, connect the output terminal of the speaker system loss circuit of the audio switch circuit to the input terminal of the speaker amplifier,
A second switching means for connecting the second output terminal of the held sound source circuit when on hold, and a means for enabling listening from the handset during a call, and disabling listening from the handset when on hold. Characteristic telephone circuit with hold tone sending function (2) A telephone circuit with a hold tone sending function according to claim 1, characterized in that when on hold, a DC voltage is supplied to the send signal detection section of the voice switch control circuit. (3) A switch means is provided between the output terminal of the power supply circuit in the telephone call circuit and the power supply terminal of the hold sound source circuit, the switching means being non-conducting during a call and conducting during a hold. A telephone circuit with a hold tone sending function as described in Scope 1.