JPH08195794A - Method and device for detecting off-hook of cordless telephone set - Google Patents

Abstract

PURPOSE: To allow a device to surely detect an off-hook state at low cost without addition of a new contact. CONSTITUTION: In a handset of the cordless telephone set or a slave set 2 in which power is supplied from the body of the telephone set or a charging base 1 via a charge terminal 5b to a battery E, a detection means 4a in a control section 4 detects a change in a voltage at a charge terminal 5b. Then when a rate of the voltage change is a prescribed value or over based on a rate of the voltage change detected by the control section 4, it is discriminated to be an off-hook state and when the changing rate is a prescribed rate or blow, it is discriminated to be a state of disconnection of power supply such as service interruption to discriminate the off-hook state from a state of power supply disconnection such as service interruption.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cordless telephone off-hook detecting method and device, and more particularly to a cordless telephone off-hook detecting method for automatically supplementing a line by lifting a handset, a handset or the like from a telephone body or a charging stand. And equipment.

[0002]

2. Description of the Related Art Conventionally, as an off-hook detecting method and device for this type of cordless telephone, for example, Japanese Patent Laid-Open No. 3-20843.
The one disclosed in No. 9 is known. FIG. 4 is a diagram showing the principle thereof. By connecting the charging voltage monitoring unit 5 to the charging terminal unit 6 of the handset 2 and connecting the charging voltage monitoring unit 5 to the control unit 4, the presence or absence of the connection with the charger 3 is detected. It is a thing.
That is, in the state where the handset 2 is on the charger 3 and is connected, the charging voltage appears at the charging terminal section 6, so the charging voltage monitoring section 5 detects this and the handset 2 is lifted to be in the off-hook state. In this case, the charging voltage disappears, so that the control unit 4 can detect the off-hook state.

An example of such an off-hook detecting circuit is a circuit having the structure shown in FIG.
In the figure, reference numeral 1 is a charging stand that serves as both a charger for charging a cordless slave unit and a storage stand for the slave unit, and also includes a master unit having a cordless handset. 2 is a cordless cordless handset, including the cordless handset of the base unit. Reference numeral 3 denotes a power supply circuit for obtaining a DC power supply for charging the slave unit 2 from a commercial AC100V power supply, which is generally composed of a transformer and a rectifier, but may be composed of a so-called switching power supply or the like. .

Reference numeral 4 denotes a control unit for controlling operations necessary for exhibiting the functions of the handset and the handset 2 such as making and receiving an incoming call. Here, only the detection of off-hook will be described. Further, the control unit 4 includes a CPU and an RO.
It is composed of a storage unit such as M and RAM and other peripheral parts, and is operated by a predetermined control program in the storage unit. Reference numeral 4b is an I / O port, which uses a dedicated IC or is configured integrally with a CPU.

In the circuit having such a configuration, the charging stand 1
The AC power input to the power supply circuit 3 is converted into a DC power supply having a predetermined voltage and current by the power supply circuit 3, and then the pair of charging terminals 5a is connected.
Is supplied to. A capacitor C is connected to the output of the power supply circuit 3 so as to absorb the output fluctuation of the power supply circuit 3 and the fluctuation of the current flowing through the load.

When the handset 2 is placed on the charging stand 1, there is a pair of charging terminals 5b at positions facing the charging terminals 5a, and the charging terminals 5a and 5b put the handset 2 on the charging stand 1. When placed, they make contact with each other and power is supplied from the charging stand 1 to the slave unit 2.

One of the charging terminals 5b of the slave unit 2 is connected to the minus terminal of the battery E and the control section 4 as an earth line, and the other of the charging terminals 5b is the I / O port 4 of the control section 4.
In addition to being connected to b, it is connected to the positive terminal of the battery E via the backflow prevention diode D.

When the handset 2 is lifted from the charging stand 1 and goes off-hook to respond to or receive an incoming call, the voltage at the charging terminal 5b decreases, which is detected by the I / O port 4b. The off-hook state of the child device 2 is detected.

[0009]

However, in the method and apparatus for detecting only the presence / absence of the voltage of the charging terminal 5b at the I / O port 4b as described above, the charging base 1 is supplied to the charging stand 1 for some reason such as a power failure. Even when the AC power supply is cut off, the control unit 4 determines that the slave unit 2 is in the off-hook state, and causes an adverse effect such as emitting unnecessary radio waves or emitting an error tone. .

As a means for preventing such an adverse effect, there is a method of separately providing a contact for off-hook detection, but it is necessary to redesign the structure and design of the telephone, resulting in an increase in the number of parts and an increase in cost. Further, since an increase in the number of contacts leads to a decrease in reliability, there has been a demand for a method and apparatus that can reliably detect only off-hook without using such contacts.

The present invention has been made in view of the above points, and an object thereof is to provide an off-hook detection method and apparatus for a cordless telephone capable of surely detecting an off-hook state without adding a new contact. Especially.

[0012]

In order to solve the above problems, the present invention is directed to a main body of a telephone or a charging stand 1 to a charging terminal 5.
In the cordless handset or handset 2 in which power is supplied to the battery E via the charging terminal 5b
The voltage detection means 4a detects a change in the voltage of the above, and when the rate of change of the voltage is equal to or more than a predetermined value, it is determined as an off-hook state, and when the rate of change is less than or equal to the predetermined value, a power failure such as a power failure It was decided to use the method to judge that

Alternatively, the main body of the telephone or the charging stand 1
In the cordless handset or the handset 2 which is supplied with power from the charging terminal 5b to the battery E, the voltage detecting means 4a in the control unit 4 detects a change in the voltage of the charging terminal 5b, and the control unit 4 It was decided to use a device that determines the off-hook state and the power-off state such as a power failure based on the rate of change in the detected voltage.

[0014]

The cordless handset or the handset 2 has a built-in battery E as a power source. To charge the battery E, the handset or the handset 2 is supplied with a power source for charging from the telephone body or the charging stand 1. Receive supply. This charging power is supplied to the handset or the handset 2 from the telephone body or the charging stand 1 via the charging terminals 5a and 5b. Therefore, by detecting whether or not the voltage of the charging power source appears at the charging terminal 5b of the handset or the slave unit 2, it can be determined whether or not the off-hook state.

However, simply detecting the presence / absence of the voltage at the charging terminal will determine the off-hook state even when the power supply of the telephone body or charging stand 1 is cut off. Therefore, a means for discriminating the power-off state and the off-hook state of the telephone body or charging stand 1 is required.

Generally, since the power supply circuit 3 for supplying voltage and current for charging the main body of the telephone or the charging stand 1 has a capacity such as a smoothing capacitor C, the power is cut off due to a power failure or the like. The voltage at the charging terminal 5b is immediately 0
It does not become V but decreases with a constant time constant. However, in the case of off-hook, the circuit is disconnected, so that the voltage drops to 0 V almost instantaneously. This state is shown in Figure 2.
Shown in (a) and (b). (A) shows the change of the voltage at the time of a power failure, (b) shows the change of the voltage at the time of an off-hook, and a vertical axis | shaft represents a voltage and a horizontal axis represents time.

Therefore, the control unit 4 of the handset or the handset 2 monitors the change in the voltage of the charging terminal 5b by the voltage detecting means 4a, and when the change rate is larger than a predetermined value, that is, the voltage immediately decreases. If it has happened, it is judged to be off-hook, and if the change rate is smaller than a predetermined value, it is judged to be in a power-off state, so that both can be distinguished.

[0018]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the basic configuration of a typical embodiment of the present invention. The configuration of this embodiment is almost the same as that of the control unit 4 of FIG. 3 in which the I / O port 4b is replaced with an A / D converter 4a as a voltage detecting means, and the same or equivalent constituent elements are designated by the same reference numerals. The description is omitted.

Control unit 4 of handset or handset 2
Monitors the voltage on the positive side of the charging terminal 5b at a predetermined cycle by the A / D converter 4a which is a voltage detecting means. Since the positive side of the charging terminal 5b is connected to the battery E through the backflow prevention diode, when the power is cut off by lifting the charging terminal 5b from the telephone body or the charging stand 1, the voltage thereof drops to 0V. When the voltage of the charging terminal 5b changes, the control unit 4 speeds up the sampling cycle, stores the value of the detected voltage in a predetermined storage area of the storage unit, and the difference from the voltage value sampled previously, The rate of change in voltage is calculated from the sampling period.

Then, the control unit 4 calculates the average value of the rate of change of the voltage calculated during the predetermined measurement time, which is larger than the threshold value stored in the predetermined area of the storage unit. In this case, it is determined that the handset or the handset 2 is in the off-hook state, and the normal operation at the time of off-hook, such as outgoing call and incoming call response, is performed.

When the rate of change of the voltage is smaller than the predetermined threshold value, the control unit 4 judges that the power supply of the telephone body or the charging stand 1 is in a power-off state and the power supply is turned off. Waits for recovery, or enters a power failure mode such as issuing a predetermined alarm. In addition, the recovery from the power failure mode is performed by monitoring the voltage of the charging terminal 5b by the A / D converter 4a as the voltage detecting means and automatically recovering by the recovery of the voltage or by an external reset operation by an alarm.

A as the voltage detecting means of the control unit 4
The / D converter 4a may use a single dedicated IC, but if it is integrated with the CPU, the circuit becomes simple, the number of parts is reduced, and the cost is not increased.

In this way, by distinguishing between the power-off state such as a power failure of the charging stand 1 and the off-hook state based on the rate of change of the voltage of the charging terminal 5b, the conventional contact can be achieved without adding a new contact. It became possible to detect off-hook reliably in the device and the method with little design change and cost increase from the device.

[0024]

As described above, according to the method of the present invention, it is possible to discriminate between the power-off state and the off-hook state based on the rate of change in the voltage of the charging terminal. Off-hook detection is now possible with a costly device.

Further, according to the device of the present invention, the change in the voltage of the charging terminal is detected, and the power-off state and the off-hook state are discriminated by the rate of the change, so that a new contact is not added. An apparatus that can reliably detect off-hook at low cost can be provided. Has the effect.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a representative embodiment of the present invention.

FIG. 2 is a diagram showing a voltage of a charging terminal, in which (a) shows a change in voltage at the time of a power failure and (b) shows a change in voltage at an off-hook.

FIG. 3 is a diagram showing a configuration example of a conventional circuit for off-hook detection.

FIG. 4 is a diagram showing the principle of a conventional off-hook detection device for a cordless telephone.

[Explanation of symbols]

 1 Charging stand (phone body) 2 Handset (handset) 3 Power supply circuit 4 Control unit 4a A / D converter 4b I / O port 5a, 5b Charging terminal C Capacitor D Diode E Battery

Claims (2)

[Claims] 1. In a cordless handset or a handset in which power is supplied to a battery from a main body of a telephone or a charging stand via a charging terminal, a change in voltage at the charging terminal is detected by a voltage detecting means, and this change in voltage is detected. An off-hook detection method for a cordless telephone, characterized in that when the rate of change is equal to or higher than a predetermined value, it is determined to be off-hook, and when the rate of change is equal to or lower than a predetermined value, it is determined to be a power-off state such as power failure. 2. In a cordless handset or a handset in which power is supplied to a battery from a main body of a telephone or a charging stand via a charging terminal, a change in voltage at the charging terminal is detected by a voltage detecting means in a control unit, An off-hook detection device for a cordless telephone, characterized in that a control section determines an off-hook state and a power-off state such as a power failure from the detected rate of change in voltage.