JPS59158696A - System for preventing collision - Google Patents

Abstract

PURPOSE:To prevent collision between an incoming and an outgoing call by detecting the incoming call by both AC and DC supervision and catching a telephone line on the premise without the incoming call in an emergency communicating device. CONSTITUTION:When an incoming signal arrives, a station terminal L2 is inverted to positive polarity. Then, since a current flows to a photodiode PD until a capacitor C1 is charged, the current is extracted by a phototransistor PT, causing a one-shot circuit 23 to trigger, the signal is converted into a one-shot output Q having long pulse width, and the pulse is fed to a control section as the 2nd incoming detection signal RING2. The control section, when informing a receiving device, confirms the presence of any incoming call by the 1st and 2nd incoming detecting signals before catching a telephone line, and confirms further the hooking-on of the telephone set, and then catches the line.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a control system for a terminal device that is connected to a receiving device via an automatic station joining line and transmits predetermined information.

[Prior art]

Conventionally, this glazed device, for example, an emergency notification device installed at a security insurance company etc. that automatically dials a remote monitoring device to notify of a fire, etc., happens to capture an incoming call signal when trying to capture a telephone line and make a call. If there is an input,
There was an inconvenience that a telephone line was connected to the caller.

[Object and structure of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to prevent the acquisition of a telephone line at the time of a call from colliding with the arrival of an incoming call signal.

In order to achieve such an object, the present invention detects incoming calls using both AC monitoring and DC monitoring, and captures the telephone line on the condition that there is no incoming call. Hereinafter, the present invention will be explained in detail using Examples.

〔Example〕

FIG. 1 is a block diagram showing the overall configuration of an emergency notification device to which an embodiment of the present invention is applied, and FIG. 2 is a circuit diagram showing its collision prevention circuit. This emergency notification device is connected to a receiving device, such as a remote monitoring device installed at a security insurance company, via an automatic station connection line, and is equipped with various sensors such as a gas detection sensor and a warning/release mode. When a predetermined activation signal is input from an operator such as a changeover switch, the telephone line is captured and the receiver is automatically dialed according to a preset dial number, and after connection, information corresponding to the activation input is transmitted. In other words, in the first part 1, the emergency notification device main body 1 transmits a multi-frequency signal similar to a button dial signal together with a predetermined subscriber address.
It is connected to the central office line via the terminal block 2. This main body 1 is
In normal use, this telephone equipment is connected in parallel to the central office line, but when necessary for testing or other purposes, it can be disconnected from the telephone equipment using disconnectors 3 and 4. It has become so. Reference numeral 5 denotes a control section including a CPU, and all operations are controlled by control signals sent from the control section 5. Reference numeral 6 denotes a station line circuit, 7 a network control section for controlling acquisition and release of the station line, and 8 a multi-frequency signal generation section. Further, 9 and 10 are specific frequencies (1650 Hz each) transmitted from the receiving device.

This is a detection unit that detects a signal of 2100Hz). 11
12 is a manually operated switch, for example, a setting section for setting the tire number and subscriber address at the time of installation; 12 is a display panel equipped with a lamp corresponding to each activation signal; 13 is a display section; The operation section 14 is an input/output interface section.

Detection from each German sensor 8 input via the input/output interface section 14 (-1-Q and operation section 13V)
, a power supply section, 17b a power supply unit, 17C a battery charging section, 17d a battery, and 18 an amplifier.

To prevent this, a collision prevention circuit as shown in Figure 2 has been added. In Fig. 2, when the disconnector 2 is in normal use, the make/break is in the opposite state from that shown, and the telephone is connected to the office line terminal L1+''2 via terminals T1 and T2. In addition, an incoming call detection circuit 21 is connected in parallel.

When the emergency notification device body 1 captures the central office line, the relay C of the network control unit γ is activated by the control signal sent from the control unit 5.
ML (not shown) operates, and the make/break of its contacts cmto and Cmtl are switched, and the station line circuit 6 is connected to the station line terminals Ll and L2.

The incoming call detection circuit 21 includes a capacitor Cl and a resistor R1 connected in series between the office line terminals L1 + L2, and a diode D1 and a photodiode PD connected in parallel in opposite directions. Note that VRl is a varistor for absorbing surges. The photodiode PD forms a photocoupler with the phototransistor PT. The output of the phototransistor PT is sent to the control section 5 via resistors R2+R3, and is also sent via a waveform shaping circuit 22 consisting of a Schmitt circuit constituted by an AND circuit AND1, an OR circuit OR1, and a resistor R4. One-shot circuit 23
is triggered, and its one-shot output Q is sent to the control section 5. Note that the relay LS connected between the incoming call detection circuit 21 and the telephone set is a relay for detecting the state of the hook switch on the telephone set, and operates with seven turns off.

In the above configuration, when a 16Hz incoming signal is input from the exchange through the office line terminals Ll and L2, the photodiode PD emits light only during the half wave when the office line terminal L2 side becomes (+), and therefore corresponds to 16Hz alternating current. The first pulse
is sent to the control unit 5 as an incoming call detection signal RINGl.

However, the incoming signal is made up of 16Hz AC connected for 1 second and disconnected for 2 seconds every month, and the exchange constantly generates such a signal, and the incoming signal that happens to be input to the connected terminal equipment. It is completely indeterminate whether it starts from the above-mentioned 1 second contact or 2 second break. Therefore, if the incoming call signal input to the emergency notification device main body 1 happens to start with a 1 second connection of 16Hz, the incoming call can be detected as described above, but if it starts with a 2 second disconnection, this method will not work. Unable to detect incoming calls.

Incidentally, the 16 Hz AC signal constitutes the incoming signal in the form of being superimposed on the constant level DC signal, and even during the above-mentioned 2 second interruption, this DC signal remains constant and does not disappear while maintaining the above-mentioned Pell. Therefore, by detecting this DC signal, incoming call detection can be performed even when the AC signal is disconnected.

In this embodiment, when an incoming signal arrives, the office line terminal "1"
The polarity of the DC voltage applied between y L 2 is Ll(+
) to L2(+), the above DC signal is detected. That is, when reversed to L2(+), the capacitor CI is charged for only a short time at 1.
Photodiode PDK current flows. Therefore, this differential output is taken out by the phototransistor PT,
After shaping the waveform, the one-shot circuit 23 is triggered to convert it into a one-shot output Q with a long pulse width, and send it to the control unit 5 as the second incoming detection signal RING2.

When receiving an activation signal from a sensor S or the like and transmitting the activation signal to the receiving device, the control unit 5 uses the first and second incoming call detection signals before operating the relay CML to seize the telephone line. It checks whether there is an incoming call, confirms that there is no incoming signal input, and then confirms that the phone is hooked on before seizing the line. In order to avoid noise operation, if only the second incoming call detection signal RING2 is obtained first, the telephone line is captured for a period of time (4 seconds in this embodiment) that sufficiently covers the 2 second AC signal interruption period. If the first incoming call detection signal RING1 is not input during that time, it is determined that there is no incoming call signal and the line is captured.

By the way, the polarity of the output sent from the exchange is usually L1.
(+), but in the case of an incoming signal, the polarity of the DC level is reversed to LL (-). Therefore, in the embodiment described above, the diode D and the photodiode PD It was possible to detect the reversal of the polarity by connecting them in the direction shown in the figure, but in rare cases, the polarity of the input from the exchange may be reversed due to incorrect connection on the exchange side. In that case, the circuit configuration described above cannot detect polarity reversal when an incoming signal arrives.

FIG. 3 shows another example of the configuration of the incoming call detection circuit 21, which makes it possible to detect polarity reversal even if there is a connection error as described above. That is, in this embodiment, a diode bridge circuit BD consisting of four diodes D2 to D5 connected in the direction shown is connected in place of the diode Dl, so that the polarity is normally reversed when an incoming signal arrives.
Whether it occurs as l(+) → L2(+) or as L2(+) → Ll(+) due to incorrect connection, e) Make sure that the charging current of capacitor C1 flows through diode PD. be. Note that the other components of the incoming call detection circuit are completely the same as those shown in FIG. 2, and therefore are omitted.

Although the above has been explained using an emergency notification device as an example, the present invention is not limited to this, and can also be applied to a terminal device that sends information to a receiving device via an automatic station subscriber line, such as a general subscriber telephone. Needless to say, the same can be applied.

〔Effect of the invention〕

As explained above, according to the present invention, damage detection is performed using both AC monitoring and DC monitoring, and by capturing the telephone line on the condition that there is no incoming call, it is possible to prevent outgoing calls from colliding with incoming calls. This makes it possible to reliably avoid inconveniences such as the line being connected to a different party than the one originally intended.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a configuration example of an emergency notification device to which the present invention is applied, Fig. 2 is a circuit diagram showing a configuration example of a collision prevention circuit representing an embodiment of the present invention, and Fig. 3 is a diagram showing a configuration example of a collision prevention circuit representing an embodiment of the present invention. FIG. 7 is a circuit diagram showing another configuration example. 1...Emergency notification device body (terminal device), 5...
Control unit, 6...Station line circuit, γ...Network control unit, 8
...Multi-frequency signal generator, 21...Incoming call detection circuit, 22...Waveform shaping circuit, 23...One-shot circuit, S...Sensor, Placement...Book Telephone, “1
1 L2...Station line terminal, CI...Capacitor, R
1-R4...Resistor, D~D5...Diode, DBφ...Diode bridge circuit. Patent applicant: Tamura Electric Manufacturing Co., Ltd. Agent: Masaki Yamakawa (and one other person) Figure 2-(6)-Figure 3

Claims (1)

[Claims] In a terminal device that sends predetermined information to a receiving device via an automatic station joining line, when making a call, the input of an incoming signal is detected by reversing the polarity of the DC signal and the presence or absence of an AC signal,
A collision prevention method characterized by capturing a telephone line on the condition that no incoming signal is input.