JPH0681177B2 - Incoming circuit - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a ring volume control circuit in an answering machine.

(Prior art and its problems) This type of conventional equipment is about 16Hz at 16Hz sent from the central office.
The 75V ringing signal was rectified, and this was used as a power source to ring the ringing tone. Since the signal sent from the station has a high original impedance of the signal, sufficient power cannot be obtained. Therefore, the ringing volume has an upper limit, and it may be inaudible because it is too small.

Further, in the answering machine, since there is no need to ring a ringing tone in an unattended place because an automatic answer is made in response to an incoming call while there is no answering machine, some of them have a switch for turning off the ringing tone. A commercial power supply is used for the automatic answering operation of the answering machine.

FIG. 1 shows an example of a conventional incoming circuit that operates only with a local power source. The operation of this circuit will be described. The line ends L ₁ and L ₂ are connected to a telephone line. When 16 Hz is sent from the telephone station, the 16 Hz AC signal applied between the line ends L ₁ and L ₂ is applied to the diode bridge DB through the capacitor C ₀ and the resistor R ₀ . The signal rectified by the diode bridge DB and converted into a direct current is stabilized by the Zener diode ZD, and the ripple is removed by the capacitor C ₁ .

IC ₁ is a tone ringer IC, and has a circuit that oscillates a ringing tone when a direct current is applied.For example, the ringing tone is a waveform obtained by amplitude-modulating an output of about 1 kHz with a signal of several tens of Hz. However, since it is not related to the object of the present invention, detailed description thereof will be omitted. The output of IC ₁ is cut off by a capacitor C ₂ for direct current, passes through a variable attenuator circuit composed of resistors R ₁ and R ₂ , and a switch SW ₁ , and is applied to a sounder S.
Sound is emitted from the sounder S. The switch SW ₁ (large) keeps the signal as it is (small), the resistor R ₁ enters and the output becomes small, and the switch SW ₁ disconnects the output from the sounder.

Since the ring tone circuit of the conventional answering machine is operated only by the local power source operation without using the commercial power source, the configuration as shown in FIG. 1 is used as the incoming circuit. If there is an incoming call during a power outage, if the incoming call is cut off, this circuit will not ring and will not respond automatically. There was a flaw.

(Object of the Invention) In order to eliminate these drawbacks, the present invention configures a ringing tone circuit through a variable attenuator when there is a commercial power source, and does not depend on the position of the variable attenuator when there is no commercial power source. First, the invention provides an incoming circuit having a circuit configuration that produces a ringing sound.

(Structure of the Invention) The present invention will be described in detail below with reference to the drawings.

FIG. 2 shows an embodiment of an incoming call circuit according to the present invention, and FIG. 3 shows an example of an answering machine set up using the incoming call circuit of the present invention.

First, the operation of the incoming circuit will be described with reference to FIG. Second
In the figure, the operation until the direct current is input to IC ₁ of the tone ringer IC is the same as that in FIG. 1, and therefore detailed description will be omitted. The output waveform of IC ₁ is applied to the primary side of the transformer T through the capacitor C ₂ . The resistor R ₃ is a matching resistor. The transformer T is inserted to separate the direct current ground between the station power supply and the commercial power supply. The secondary side which is the output of the transformer T is connected to the common side of the contact p of the relay P. When the power source V _B is applied to the relay P, the operation is a relay, and as V _B , an output converted from a commercial power source into a direct current is usually used. Therefore, since the P relay operates when there is a commercial power source, the ringing signal is switched to the meter side of the relay contact p. This is input to the variable attenuation circuit composed of the resistors R ₄ , R ₅ and the switch SW ₁ . Its output is applied to one of the inputs of a speaker amplifier (SPA) IC ₂ operating from a power supply V _B. The other input of IC ₂ is used, for example, for playback sound monitoring. The output of IC ₂ is output as sound from the speaker SP that is always connected via the capacitor C ₃ . SW
₁ has three contacts, and there are three contacts for changing the resistance value in series to increase or decrease the volume and disconnect the volume as an open circuit.
When there is no commercial power source (during a power failure), the P relay is restored, so the call signal is switched to the break side of the relay contact p. In this case, since V _B is not applied, the output impedance of IC ₂ is higher than that during operation, so that the sound of the tone ringer is output from the speaker SP.

With such a configuration, when there is a commercial power source, the ringing signal will be output from the speaker via the volume control circuit including signal interruption, and it will be smaller or larger than when the local power source is operating with limited power. It is also possible to freely turn off the switch. In addition, since the variable attenuation circuit is not passed during a power failure, there is an effect that the ringing tone can be heard at a predetermined volume even if the switch is off.

Next, FIG. 3 shows an example in which this incoming circuit is used in an answering machine. In FIG. 3, 1 is a line connection terminal L ₁ / L ₂ , 2 is a hook switch, 3 is a communication circuit network, 4 is a transmitter, 5 is a receiver, and 6 is a ringing tone oscillation circuit configured as shown in FIG. , 7
Is a signal transformer, an amplifier for 8 speakers, 9 is a speaker,
Reference numeral 10 is a ring volume control circuit, 11 is a recording amplifier, 12 is a reproduction amplifier, 13 is an incoming signal detection circuit, 14 is a control circuit for controlling analog gate, relay, motor, rotation detection, etc., 15 is a commercial power supply A power supply circuit as a power source, 16 is a P relay that operates when there is a power source, 17 is a circuit closing relay that operates with the output of the control circuit 14, 18 is a contact L of a relay L, and 19 is a P
Relay contacts p, 20, 21, 22 are ON-OF by the output of the control circuit 14.
F analog gate, 23 recording / playback head, 24 magnetic tape, 25 motor for driving tape 24, 26 tape 24
Is a rotation detection circuit that is connected to a reel such as the take-up side and detects the rotation of the reel.

When it is used as a telephone, when the hook switch HS is closed (off-hook), the line end L ₁ / L ₂ → HS → connected to the telephone network, a DC loop is formed for the station and connected to the telephone network. A call can be made using the transmitter 4 and the receiver 5 that have been set up.

In order to operate as an answering machine, an incoming signal from the station is first detected by an incoming signal detection circuit (IR) 13, and the output causes the control circuit 14 to operate the relay L. Then, since the relay contact (1) 18 inserted in parallel with the hook switch HS operates, a DC loop is formed for the station in the same manner as described above. Then, the control circuit 14 first operates the motor 25 to reproduce the response message recorded on the tape 24. This is picked up by the head 23,
[Analog gate 22 → playback amplifier 12 → signal transformer 7]
Is sent to the line through the route. When the end of the response message is detected, the control circuit 14 closes the analog gate 22 to 21
Open and record the signal from the line on the tape 24 through the route of [signal transformer 7 → recording amplifier 11 → analog gate 21 → head 23].

The position of the response message and the recording position of the message can be controlled by controlling the position from the tape start end by the rotation detection circuit 26. The detailed operation is not related to the essence of the present invention, so the description thereof will be omitted.

The signal at the line end can be monitored by the transformer 7, the analog gate 20, the speaker amplifier 8, and the speaker 9. Incoming circuit 6,
The relay P, the ring volume control circuit 10, the amplifier 8 and the speaker 9 form the ring tone circuit shown in FIG.

The answering machine is originally used when the user is away. Therefore, it is better not to ring the ringing tone when an incoming call arrives. This is because it may be possible to externally determine that the user is out when the ringing tone continues to sound. Therefore, the ring tone may be turned off when setting the normal absence. Since the answering machine has a function to monitor when answering automatically, you can set it as an answering machine when you are in the room to do so-called absence. At this time, with the circuit according to the present invention, even if the telephone answering machine stops operating due to a power failure, a ringing tone can be heard, so that it is possible to prevent the important telephone from being unknowingly taken off.

(Effects of the Invention) As described above, according to the present invention, it is possible to freely adjust the ringing volume including turning off when energized, and even if it is turned off, it is possible to listen at a constant volume during a power failure. There is.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an example of a conventional incoming circuit, FIG. 2 is a circuit diagram showing an example of the incoming circuit according to the present invention, and FIG. 3 is a construction of an answering machine using the incoming circuit according to the present invention. It is a block diagram showing an example in the case of doing. 1 ... Line connection terminals (L ₁ , L ₂ ), 2 ... Hook switch (HS), 3 ... Call circuit network (HYB), 4 ... Transmitter (T), 5 ... Receiver (R) , 6 ... Ring tone oscillation circuit (TR), 7 ... Signal transformer, 8 ... Speaker amplifier (SPA), 9 ... Speaker (SP), 10 ... Ring volume control circuit (ATT), 11 ... Recording amplifier (REC), 12 …… Playback amplifier (PLAY), 13 …… Incoming signal detection circuit (IR), 14 ……
Control circuit (CPU), 15 ... Power supply circuit (POW), 16 ... P relay, 17 ... L relay, 18 ... L relay contact 1, 19 ...
… P relay contacts p, 20,21,22 …… Analog gate,
23 …… recording / playback head, 24 …… magnetic tape, 25 …… motor (M), 26 …… rotation detection circuit (CP), DB …… diode bridge, IC ₁ …… tone ringer IC, SW ₁ …… switch , S ... Sounder.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisataka Fujita 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Makoto Shimizu 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (56) References JP-A-49-46301 (JP, A) JP-A-52-127012 (JP, A)

Claims (1)

[Claims] 1. A ringing signal generating circuit for generating a ringing tone signal in response to an incoming signal from a line, an amplifier for tone amplification operated by a commercial power source, a speaker always connected to the output side of the amplifier, and an attenuation amount. When there is a variable attenuation circuit that can be set to infinity and a power source input from a commercial power source, the output of the ringing signal generation circuit is connected to the input of the amplifier via the variable attenuation circuit, and when there is no commercial power source input. A receiving circuit provided with switching means which operates so as to directly connect the output of the ringing signal generating circuit to the connection position of the amplifier and the speaker by utilizing the increase of the output impedance of the amplifier.