JPS63279644A - Circuit for detecting incoming signal and howler signal of telephone set - Google Patents

Abstract

PURPOSE:To enable to detect an incoming call and mis-operation with simple circuit constitution by providing a signal identification circuit using a signal detection circuit provided to a telephone line side of a hook switch so as to detect an incoming signal and a howler signal and identifying the incoming signal and the howler signal from the hook switch information and the output of the signal detection circuit. CONSTITUTION:If a hook switch 5 is closed (off-hook) state by mis-operation of a telephone set and a howler signal is fed to line connection terminals 1, 2, it is inputted to a signal detection circuit 21 similarly to the incoming signal and an output of the signal detection circuit 21 goes to a low level. In this case, since the hook switch 5 is in the closed state, a current flows to a diode bridge 29 from the line connection terminals 1, 2, a collector voltage of a photo transistor 32 goes to a low level and the off-hook information of the hook switch 5 is represented. The off-hook information and the low output of the signal detection circuit 21 are inputted to a NOR gate 37 of a signal identification circuit 34 to bring the howler signal detection output terminal to a high level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a circuit for detecting an incoming call signal in a telephone set and for detecting a howling sound when the telephone receiver is disconnected due to an erroneous operation or the like.

[Prior Art] Fig. 2 is a circuit diagram of a conventional telephone having a countermeasure for removing the handset, as disclosed in, for example, Japanese Patent Laid-Open No. 61-117960. In the figure, (1) and (2) are telephone lines connection terminal, (3) is a capacitor, (4) is a capacitor (3)
) and the incoming bell connected in series between the connection terminals (1) and (2), (5) and (6) are hook switches, (7) is a dial circuit, (8) is a signal detection circuit, (9) is the telephone circuit,
(10) is an external power supply, (11) and (12) are indicator lamps, (13) is a diode bridge, (14) is a relay,
(14a) is a contact driven by the relay (14), (15) is a relay, (15a) to (15e) are contacts driven by the relay (15), (8a) is a signal detection circuit (8) It is a contact driven by

FIG. 3 shows the internal configuration of the signal detection circuit (8) in FIG. 2, where (16) is a band pass filter, (1
7) is a pulse converter, (18) is a count circuit, (19)
) is a clock generation circuit, and (20) is a relay.

Next, the operation will be explained based on FIGS. 2 and 3. When making a call, when the caller closes the hook switches (5) and (6) (off-hook state), the telephone circuit (9) connects the connection terminals (1) and (2) and the contact (15b). (15C)
It is connected to a telephone line via a dial circuit (7), and a call operation is performed by sending a dial signal corresponding to a telephone number to the telephone line side.

At this time, if the caller is busy, the switchboard (not shown) transmits 5QIPM at 400Hz, for example, according to an example of preparing application materials for technical standards compliance certification issued by the Telecommunications Terminal Equipment Certification Association.
A busy tone (intermittent 60 times per minute) is sent to the caller.

The busy sound is processed by a band pass filter (1) shown in FIG.
6) removes signals other than 400 Hz, rectifies and smoothes them in a pulse conversion circuit (17), and while the signals are being output, a count circuit (18) counts pulses from a clock generation circuit (19).

Here, if the caller makes a mistake such as forgetting to return the hook switches (5) and (6) (on-hook) and the predetermined count number is exceeded, the counting circuit (18) energizes the relay (20). do.

When the contact (8a) is closed by the relay (20),
Since the hook switch (6) is in the closed state, the relay (15) is energized. Therefore, when the contact (15d) closes, the control state is self-maintained, and when the contact (15e) closes, the indicator lamp (11)
lights up.

Furthermore, by opening the contacts (15b) and (15c), the telephone line is disconnected from the telephone circuit (9) and placed in a standby state, and by closing the contact (15a), the incoming call (
4) in parallel with a diode bridge (13) and a relay (1
4) Connect.

In this state, the incoming signal is connected to connection terminals (1) and (2).
When applied to the incoming signal, this incoming signal rings the incoming bell (4) via the capacitor (3) and is rectified by the diode bridge (13) to drive the relay (14).

By driving the relay (14), its contacts (14a)
closes, and the indicator lamp (12) lights up to indicate an incoming call.

[Problems to be Solved by the Invention] Since the conventional incoming signal/howler signal detection circuit is configured as described above, a circuit for detecting erroneous operation is required in addition to a circuit for detecting incoming calls, and a filter circuit or There were problems such as the need to add a complicated circuit such as a counter circuit.

This invention was made to solve the above-mentioned problems, and the object is to obtain an incoming signal/howler signal detection circuit that can detect incoming calls and detect erroneous operations with a simple circuit configuration. .

[Means for Solving the Problems] The incoming signal/howler signal detection circuit according to the present invention detects incoming signals and howler signals using the signal detection circuit provided on the telephone line side of the hook switch, and also detects the incoming call signal and howler signal. The apparatus includes a signal identification circuit that identifies an incoming signal and a howler signal from the output of the signal detection circuit.

[Operation] The signal identification circuit in this invention outputs a howler signal detection signal when the hook switch is in a closed state and the signal detection circuit detects a signal, and when the hook switch is in a closed state and the signal detection circuit detects a signal. In such cases, by outputting an incoming signal detection signal, it is possible to detect incoming calls and erroneous operations with a simple circuit configuration.

[Embodiment] An embodiment of the present invention will be described below with reference to FIG. 1, in which the same parts as in FIG. 2 are given the same reference numerals.

In FIG. 1, (21) is a signal detection circuit that detects an incoming signal and a howler signal;
A current limiting resistor (22), a Zener diode (23), a light emitting diode (24), and a phototransistor (25) that receives light from the light emitting diode (24) are connected in series to the capacitor (3). , resistance (27
) and a capacitor (28) connected to the emitter of the transistor (26).

(29) is connected to the connection terminal (1) via the hook switch (5).
) and (2), a diode bridge connected between (30
) is a light emitting diode, which is connected between the output terminals of the diode bridge (29) via a resistor (31). (
32) is a phototransistor that receives light from the light emitting diode (30), and is connected to an external power supply (33) via a resistor (33).
10).

(34) is a signal identification circuit, and this signal identification circuit (34) is a signal identification circuit.
4) is NOT game) (35) and AND gate (36)
, a NOR gate (37), and an incoming signal detection output terminal (38) and a howler sound detection output terminal (39).

According to the above-mentioned technical standard compliance certification application material preparation example, the alarm sound sent from the exchange is generally a 400 Hz gradually increasing continuous signal, and the sending level is about 32 to 36 dB1. On the other hand, the calling signal which is the incoming signal is 16H2 and 75
V, which is extremely large compared to other signal levels of −4 dBm or less.

Next, the operations when receiving an incoming call signal and when receiving a missed signal due to an erroneous operation will be explained.

When receiving an incoming call signal, the ringing signal is connected to the line connection terminal (1)
, (2), capacitor (3), resistor (2:l
Voltage is applied to the Zener diode (23) and the light emitting diode (24) through the zener diode (23) and the light emitting diode (24).

At this time, the resistor (22) and Zener diode (23)
zener voltage is selected so that the light emitting diode (24) emits light when an incoming signal is applied.

Therefore, when an incoming signal is received, the light emitting diode (24
), the phototransistor (25) and the transistor (26) turn on, and the transistor (26) turns on.
26), that is, the output of the signal detection circuit (21) changes from the normal H1gh level to the Low level.

At this time, depending on the charging/discharging time constant of the capacitor (28),
Prevent malfunctions due to excessive response of the signal detection circuit. Also, at this time, since the phone is in standby mode, the hook switch (5) is in the open (on-hook) state, no current flows through the light emitting diode (30), and the phototransistor (32) is in the off state. Therefore, the collector output voltage of the phototransistor becomes Hlgh, which represents on-hook information of the hook switch (5).

The output of the signal detection circuit (21) and the hook switch (5)
) is input to the signal identification circuit (34), and the incoming signal detection output terminal (38) is set to H1gh level by the NOT gate (35) and AND gate (36).

The hook switch (5) may close (
The system enters the off-hook state, and the howler signal is sent to the line connection terminal (off-hook).
1) and (2), it is input to the signal detection circuit (21) in the same way as the incoming signal, and the Zener voltage of the resistor (22) and Zener diode (23) is applied not only to the incoming signal but also to the howler signal. By selecting to operate at 400 Hz and 32 dBm, the output of the signal detection circuit (21) becomes Low.

At this time, since the hook switch (5) is in the closed state,
From the line connection terminals (1) and (2) to the diode bridge (
29), the light emitting diode (30) emits light and turns the phototransistor (32) on.
The collector voltage of the phototransistor (32) becomes Low, representing off-hook information of the hook switch (5). This off-hook information and the low level of the signal detection circuit (21)
The output is the NOR gate (37) of the signal identification circuit (34)
and the howler signal detection output terminal (39) is H1g.
h level.

In the above embodiment, hook switch information is detected using a light emitting diode (30) and a phototransistor (32), but a plurality of contacts of the hook switch (5) may be input as the hook switch information.

[Effects of the Invention] As described above, according to the present invention, an incoming signal and a howler signal are detected by the same signal detection circuit, and when the hook switch detects an on-hook signal, the incoming signal is detected, and the hook switch detects an off-hook signal. Since the structure is configured so that the case where a signal is detected is detected as a howler signal, an incoming signal/howler signal detection circuit that can detect incoming calls and detect erroneous operations with a simple and inexpensive circuit configuration can be obtained. There is

[Brief explanation of the drawing]

FIG. 1 shows an incoming call signal of a telephone according to an embodiment of the present invention.
FIG. 2 is a circuit diagram showing a howler signal detection circuit, FIG. 2 is a circuit diagram of a conventional telephone having a countermeasure against disconnection from the handset, and FIG. 3 is a block diagram of a detection circuit which is a circuit component of FIG. 2. In the figure, (1) and (2) are connection terminals, (5) is a hook switch, (9) is a telephone circuit, (21) is a signal detection circuit, and (34) is a signal identification circuit. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent Masuo Oiwa (patent attorney) (and 2 others) Sponsored to write amendments to Figure 2 procedures) 1. Indication of the incident Patent application No. 62-115136 No. 2
, Name of the invention: Telephone i°'1 signal/hauler f signal detection circuit
+1. %71'Pa ・＼巳- 3. Person who makes corrections
1.X? =・Representative: Moriya Shiki 11, Agent address: 5, Mitsubishi Electric Corporation, 2-2-3 Marunouchi, Chiyoda-ku, Tokyo, Japan Detailed description of the invention and drawings in the subject specification of hliiE. 6. Contents of supplementary IF

Claims (1)

[Claims] In a telephone equipped with a hook switch that is installed on a line that connects a telephone line connection terminal and a telephone circuit and connects and disconnects the line, the hook switch is connected to the telephone line connection terminal side of the hook switch to transmit an incoming signal and a howler signal. a signal detection circuit that detects the signal, and inputs the detection signal of the signal detection circuit and the open/close signal of the hook switch, and when the hook switch detects a signal in the open state, it is regarded as an incoming signal, and the hook switch is in the closed state. 1. An incoming signal/howler signal detection circuit for a telephone, comprising a signal identification circuit that identifies the signal as a howler signal when the signal is detected.