JPH08273070A - Call-back device - Google Patents

Abstract

PURPOSE: To provide the call-back device with which the child or the aged of a monitoring object away from a prescribed place can be called back without seraching him and further, any complicated configuration is not required even when the number of objects is plural. CONSTITUTION: A radio wave for calling a hand set 2 is transmitted from the transmission part of a base unit. At a reception part 23 of the hand set 2 where that radio wave is received, the electric field strength of the received radio wave is compared with a set value previously set by a level adjuster 23a. When that strength is lower than the set value, the person who carries the hand set 2 is called by a speaker 27a and attention is called to surrounding persons by an LED 28 or a display 29. At the same time, the output of the transmission part 24 is up and the data of step sensor 30 or an acceleration sensor 31 are transmitted toward the base unit. When the electric field strength is higher than the set value, a radio wave (answer back) for reporting the absence of abnormality is transmitted from the transmission part 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for recalling a person who has left a predetermined area.

[0002]

2. Description of the Related Art There has been proposed an alarm device for issuing an alarm when an infant or a demented elderly person (monitored person) who is poor in situational judgment ability is separated from a caregiver (monitored person) by a certain distance or more.
For example, the stray child prevention device disclosed in Japanese Unexamined Patent Publication No. 4-125800 is used when a carer has a receiver and weak radio waves emitted from a transmitter of a cared person at predetermined time intervals cannot be received for a certain period of time or longer. Then, the alarm is issued. In addition, the wireless confirmation monitoring system disclosed in Japanese Patent Laid-Open No. 166696/1990 discloses a wireless confirmation monitoring system which is equipped with a wireless transmitter when a monitoring target person is separated from a transceiver arranged in a predetermined area by a certain amount or more. It informs the observer.

In any of these devices and systems, the monitored person has a transmitter that emits a radio wave, and the monitored person receives the radio wave and checks the signal strength of the monitored person. It is configured to know that you have left.

[0004]

However, in the above-mentioned device or system, since the monitoring person cannot receive the radio wave of the transmitter of the monitoring person, the monitoring person is the monitoring person or the predetermined person. Just knowing that they were at least a certain distance from the location made it impossible to know where the surveillance subject was currently, and the surveillance officer had to search around. In particular, it was very difficult to find a person to be monitored in a crowded place.

Further, when the number of persons to be monitored becomes plural, a plurality of transmitters are also required. Therefore, it is necessary to use a plurality of frequencies or use the same frequency in a time-sharing manner by controlling the time. However, there is also a problem that the equipment and facilities such as the transmitter and the receiver are complicated. Furthermore, it is possible to know the problem that the monitoring person mistakenly thinks that the transmission stop due to the battery exhaustion of the transmitter is due to the movement of the monitored person, when the monitored person left the predetermined place, and to what extent. There was also the problem that it could not be done.

[0006] In addition, when the monitored person leaves the predetermined place, the fact is notified to the monitored person and the surrounding people,
I couldn't even encourage them to go back to their designated places.

The present invention has been proposed in view of the above problems, and it is possible to call back even if an infant or an old person to be monitored is separated from a predetermined position, and even if the number of monitored objects is increased, it is easy. It is an object of the present invention to provide a recalling device that can be realized with various configurations and can know the movement information.

[0008]

In order to solve the above-mentioned problems, a recall device according to a first aspect of the present invention comprises a slave unit comprising a receiving means, a notifying means and a transmitting means, a receiving means, an alarming means and a transmitting means. And a receiving device of the child device, the receiving device is a receiving device that outputs a warning signal when the electric field strength of the radio wave from the parent device is less than or equal to a set value, and outputs a safety signal when the electric field strength of the child device is above the set value. The notification means of is a notification means for notifying the outside when a notification signal is detected, the transmission means of the slave unit is a transmission means for transmitting a radio wave when a safety signal is detected, and the reception means of the master unit is a radio wave from the slave unit. The receiving means that outputs an alarm signal when the electric field strength is less than or equal to the set value is used, and the alarm means of the parent device is an alarm means that issues an alarm when an alarm signal is detected.

In the call back device of the second aspect, the transmitting means of the parent device of the call back device of the first aspect is a transmitting device for transmitting a radio wave for selecting and calling the child device. The method of selecting and calling the slave unit may be to change the frequency, modulate the radio wave with a specific low-frequency tone signal, or use code squelch, DTMF, or the like.

According to a third aspect of the present invention, there is provided a recalling device for displaying the time when the warning signal is detected and / or the elapsed time from the time when the warning means of the parent machine of the recalling device according to the first aspect is displayed. It is configured to have. According to a fourth aspect of the present invention, there is provided the call back device according to the first aspect, wherein the notification means of the child device of the call back device stores the stored character information and / or
Alternatively, the notification means is provided to read out the audio information when the notification signal is detected and notify it.

According to a fifth aspect of the present invention, there is provided a call back device comprising a slave unit having a receiving unit, a notifying unit, a transmitting unit and a movement detecting unit, and a master unit having a receiving unit, an alarm unit and a transmitting unit. The receiving means of the device is a receiving means that outputs a notification signal when the electric field strength of the radio wave from the parent device is below the set value and outputs a safety signal when the electric field strength of the parent device is above the set value. As the notification means for notifying outside, the movement detection means is the movement detection means for counting the vibration due to walking from the time when the notification signal is detected and outputting it as movement data, and the transmission means of the slave unit after the safety signal is detected and after the notification signal is detected. As a transmission means for transmitting the movement data, the reception means of the parent device as a reception means for demodulating the radio wave from the child device to output the movement data and for outputting an alarm signal when the electric field strength of the radio wave is less than or equal to a set value, Base unit And an alarm means for issuing an alarm when it detects an alarm signal and displays the movement data the warning means.

In the call back device of the sixth aspect, the movement detecting means of the call back device of the fifth aspect is the movement detecting means for detecting the acceleration from the time when the notification signal is detected and outputting it as movement data. In the call back device of the seventh aspect, the transmitting means of the slave unit of the call back device of the fifth and sixth aspects is the transmitting means for increasing the transmission output from the time when the notification signal is detected.

[0013]

In the call back device of the first aspect, the reception means of the slave unit receives the radio wave transmitted by the transmission means of the master unit. The reception means of the slave unit outputs a notification signal when the electric field strength of the received radio wave is less than or equal to a set value, and outputs a safety signal when the electric field strength of the received radio wave is greater than or equal to the set value. The notification means that has detected the notification signal calls out to the owner of the child device or the people around it with sound or light. On the other hand, when the safety signal is detected, the transmitter of the slave unit transmits the radio wave.

The receiving means of the master unit outputs an alarm signal when the electric field strength of the radio wave from the slave unit is less than or equal to the set value. And
The alarm means issues an alarm when it detects an alarm signal.

In the call back device of the second aspect, the transmitting means of the base unit transmits a radio wave for selectively calling the slave unit by changing the frequency or modulating the radio wave with a tone signal of a specific low frequency. The reception means of the slave unit outputs a notification signal when the electric field strength of the received radio wave is less than or equal to a set value, and outputs a safety signal when the electric field strength of the received radio wave is greater than or equal to the set value. Subsequent operation of the child device and operation of the parent device are the same as in the case of claim 1.

In the call back device of the third aspect, the alarm means of the master unit displays the time when the alarm signal is detected and the elapsed time from this time by the display means. In the call back device according to the fourth aspect, when the notification means of the slave unit detects the notification signal, it reads the character information or voice information stored in advance and notifies the outside by characters or voice.

In the call back device of the fifth aspect, the receiving means of the slave unit outputs the notification signal when the electric field strength of the radio wave from the master unit is less than or equal to the set value, and outputs the safety signal when the electric field strength of the parent unit is above the set value. When the notification signal is detected, the notification unit of the slave unit notifies the notification signal by sound or light. The movement detecting means counts the vibration due to walking from the time when the notification signal is detected and outputs it as movement data.
The transmission means of the slave transmits the movement data when the safety signal is detected and after the notification signal is detected.

The reception means of the master unit demodulates the radio wave from the slave unit and outputs the mobile data if there is movement data, and outputs an alarm signal when the electric field strength of the radio wave is less than a set value. The alarm means of the base unit displays the movement data and issues an alarm when an alarm signal is detected.

In the call back device of the sixth aspect, the movement detecting means detects the acceleration from the time when the notification signal is detected. This is output as movement data. This movement data is transmitted by the transmission means of the child device. The subsequent operation is the same as that of the fifth aspect. In the call back device of the seventh aspect, the transmission output of the transmission means of the slave increases when the transmission means detects the notification signal.

[0020]

The present invention will be described below in detail with reference to the drawings showing the embodiments. The recalling device of the present invention is for monitoring the wandering of an elderly person in a nursing home. FIG. 1 is a block diagram of a master unit installed on the observer side, FIG. 2 is a block diagram of a slave unit of an elderly person to be monitored, FIG. 3 is a perspective view of the child device, FIG.
Is an explanatory view of the use of the recalling device according to the present invention, FIG. 5 is a flowchart of the master unit, and FIG. 6 is a flowchart of the slave unit. The recalling device uses FM waves in the UHF band.

In FIG. 1, reference numeral 1 is a master unit of a call back device installed on the nursing home side, 11 is an external antenna installed on the roof of the nursing home D of FIG. 4, and 12 is an external antenna 1.
1 is a filter for sharing the transmitter / receiver, 13 is a receiver that receives and demodulates a radio wave of frequency f1, 13a is a level adjuster that adjusts the level of the squelch built in the receiver 13, and 14 is a plurality of children. A transmitting unit for transmitting radio waves having frequencies corresponding to the number of devices, and a CPU 15 for controlling the operation of each unit of the base unit 1. Reference numeral 16 is a memory that stores ID codes of a plurality of slave units and transmission frequencies corresponding to the ID codes, and stores an operation control program. Reference numeral 17 is an alarm for notifying that the slave unit has left, and 18 is a display device for displaying various data. Reference numeral 19 is a clock, and reference numeral 14a is a modulation microphone for directly contacting the slave unit by a real voice in an emergency. At this time, in the slave unit, the demodulated signal of the receiving unit is directly input to the amplifier. The base unit 1 is transmitting and receiving at the same time.

Here, the receiving unit 13 serves as the receiving means of the base unit,
The transmission unit 14 serves as the transmission means of the parent device, and the CPU 15 and the alarm device 1
7 and the display 18 and the clock 19 serve as alarm means, and the display 18
Corresponds to the display means.

In FIGS. 2 and 3, 2 is a child device of a call-back device of an old person to be monitored, 21 is an antenna also serving as a hanging string, 22 is a filter for sharing the antenna 21 between the transmitting and receiving portions, and 23. Is a receiving unit that receives and demodulates a radio wave of frequency f2, 23a is a level adjuster that adjusts the level of the squelch built in the receiving unit 23, and 24 is the frequency f
This is a transmission unit that transmits the radio wave of 1. Reference numeral 25 is a CPU for controlling the operation of each part of the child device 2, 26 is a memory for storing voice information and character information such as a voice of a close relative of an old person to be monitored and favorite music, and 27 is voice information of the memory 26. Or an amplifier for amplifying the sound from the master unit 1 and outputting it from the speaker 27a, 28 is an alarm LED blinking when the amplifier 27 is operating, 29 is a display for reading and displaying the character information of the memory 25, and 30 is a child. It is a step number sensor that counts the number of steps when the machine 2 feels a sway.

Here, the receiving unit 23 serves as a receiving means of the slave unit,
The transmitting unit 24 serves as a transmitting unit of the slave unit, and the CPU 25 and the amplifier 2 are used.
7, the speaker 27a, the LED 28, and the display 29 correspond to the notifying means, and the step count sensor 30 corresponds to the movement detecting means.

Next, the operation of the call back device according to the present invention will be described with reference to FIGS. 3 and 4, weak radio waves are emitted from the external antenna 11 on the roof of the nursing home D. Then, the reception frequency f2
An old man A with a child device 2 has a radius of 50 m from the antenna 11.
Within the strong range E of radio waves within, the handset 3 with the reception frequency f3
Old man B with a radius of 50m from antenna 11 to 1
It is assumed that, within the range F up to 00 m, the old man C having the slave unit 4 having the reception frequency f4 is located outside the range F at a weak radio wave point. In addition to this, 7 cordless handsets with different transmission frequencies,
There are 10 slaves for convenience. The transmission frequency is frequency f1.

Here, the level adjuster 13a of the base unit 1 is adjusted so that the alarm signal of the base unit 1 is output when the distance between the antenna 11 of the base unit 1 and the handset is 50 m or more in sight. Has been done. Similarly, the level adjuster of each slave unit is adjusted so that the notification signal of each slave unit is output when the line of sight is 100 m or more away.

First, the operation of the slave unit will be described with reference to FIGS. When the power of the child device 2 is turned on and operated, step S
At 11, the reception is started at the frequency f2. Then step S
At 12, it is checked whether the squelch of the receiving unit 23 is open. Since it is in the nursing home D that the power is turned on, base unit 2
The electric field strength of the radio wave of the frequency f2 from is above the set value, and the safety signal is output from the receiving unit 23. Then step 1
At 3, the CPU 25 controls the transmitter 24 to transmit the radio wave of the frequency f1 for a certain period of time (this operation is hereinafter referred to as answer back). When the transmission is completed, the process returns to the reception in step S11. This operation is repeated. The same applies to the child device 3 of the old man B in the range F.

If, like the old man C with the child device 4, the range F
If the radio wave of the frequency f3 of the base unit 1 can be received, the electric field strength is smaller than the set value and the squelch does not open in step S12, so that a notification signal is output from the reception unit 23. It proceeds to step S14. Therefore, the transmission output of the transmission unit 24 is increased and the step count sensor 30 is increased.
Is started. Then, in step S15, the voice information and the character information recorded in the memory 26 are read out, the voice information is amplified by the amplifier 27, and the speaker 27a is read.
To output from. Further, in step S15, in case the person cannot return to the nursing home D because he / she does not know the way, he / she blinks the LED 28 for notifying the surrounding people and displays the character information on the display 29. Therefore, even if the old man C having the child machine does not return to the nursing home D, there is a high possibility that the people around him will notice and contact him.

The utterance / display operation is performed once for 3 seconds, and this operation is repeated 10 times in step S15. When that ends, the process proceeds to step S16, and the step count data of the step count sensor 30 that started counting in step S14 is transmitted to the master device 1 at the frequency f1.

Next, the operation of the base unit 1 will be described with reference to FIGS. In the memory 16 of the parent device 1, transmission frequencies for 10 child devices are stored. The CPU 15 reads the data from the first to tenth slaves from the memory 16 and processes them in order, using the time signal of the clock 19 as a reference. An initial value of 0 is given in step S1,
In step S2, preparation for transmission to the first slave unit 2 is made.

In step S3, the transmission frequency f2 corresponding to the slave unit 2 is read from the memory 16, and in step S4, the transmitting section 14 continues to transmit the radio wave of frequency f2 for 3 seconds. This time compensates for the instability of the electric field strength on the handset side due to fading. As shown in FIG. 4, the elderly person A having the child device 2 is in the area E near the nursing home D, so that the receiving portion 23 of the child device 2 outputs a safety signal and the transmitting portion 24 sends the radio wave of the frequency f1. Send. Since this transmitted radio wave is sufficiently strong, the squelch of the receiving unit 13 opens in step S5, and it is determined that the slave unit 2 has no abnormality, which is displayed on the display unit 18 in step S6. The alarm 17 does not operate naturally.

In step S7, the number of slave units is checked. Specifically, since there are 10 slave units to be monitored, steps S2 to S7 are performed until N becomes 10 in step S7.
The above operation is repeated, and the status of the radio waves transmitted from the slave units is checked one by one and displayed sequentially. In this way 1
When all 0 slaves have been checked, step S1
Return and repeat the check from the first child device again.
Since the transmission time in step S4 is 3 seconds, it is 30 with 10 units.
It is the required time in seconds.

Next, the operation of the base unit 1 when the distance is 50 m or more like the old man B having the handset unit 3 in FIG. 4 will be described. In step S3, the transmission frequency f3 corresponding to the child device 3 is read out, and in step S4, the radio wave of the frequency f3 is transmitted. Then, the receiving unit of the handset 3 receives the radio wave, outputs a safety signal, and transmits at the frequency f1 in the same manner as the handset 2. However, since the electric field strength of the radio wave is less than or equal to the set value in base unit 1, step S5
Therefore, the squelch does not open and the process proceeds to step S8. Step S
In No. 8, in addition to displaying on the display unit 18 that the slave unit currently being called is the slave unit 3, the sound of the alarm unit 17 informs that the elderly person B is 50 m or more away from the nursing home D. At this time, the slave 3 and the current time are recorded in the memory 16.

After that, when the old man B moves further away from the position shown in the figure and goes out of the range F, the operation is the same as the operation of the child device 4 described above, and even if the parent device 1 transmits at the frequency f3, the answerback is performed. There is no. However, since the handset unit 3 transmits the step count data to the base unit 1 every 30 seconds after the previous transmission, if the portable unit base unit or the like receives it, the footsteps can be roughly grasped. . In this case, the transmission to the other child device is stopped, only the radio wave of the child device 3 owned by the missing old man B is received, and the search is performed based on that.

In this way, when the old man B with the child device 3 goes out of the range F, the observer immediately understands it, but in the unlikely event that he does not notice it, he goes somewhere far away. In case of the above, after recognizing how far from the time previously recorded in the memory 16, the portable master unit using a directional antenna instead of the external antenna 11 is searched. That is, the child machine 3 of the missing old man B
When searching while transmitting radio waves at the reception frequency f3 of
When approaching to a position equal to or higher than the electric field strength setting value of the handset 3, the squelch of the handset 3 opens and returns a transmission, so that the direction of arrival of the radio wave can be searched with a directional antenna.
It can be seen that the target old man (slave) is at a position of about m. If the transmission output is reduced when approaching to a certain extent, the squelch of the child device closes and the speaker speaks, so that the person to be monitored can be easily found. In some cases, the microphone provided in the transmitting unit of the portable base unit may be called directly to search for the voice.

According to this method, the person to be monitored can be easily searched for not only in a small number of people but also in a crowd. In addition, since the slave unit always emits radio waves to the master unit once every 30 seconds, it is immediately known that the battery is exhausted.

By adjusting the levels of the level adjusters of the master unit and the slave unit, the operating range of the alarm means or the alarm means can be set freely and easily. In the embodiment, the transmission frequency of the parent device is changed as a method of selecting each child device, but tone squelch and DTM are used at the same frequency.
You may select using F code, code squelch, etc.
The portable master unit may have a built-in antenna, or may use separate antennas for transmission and reception for both the master unit and the slave unit. Further, if transmission and reception are not performed simultaneously, an antenna switch may be used instead of the filter. Good.

The child device 5 attached to the hat of FIG. 7 is a recalling device used as a set with the parent device having only the transmitting function.
It is a simple type including a built-in receiving unit (not shown), a voicing unit (not shown) having a speaker 5a, an antenna 5b, a display 5c, and a solar cell 5d as a power source. This is a configuration in which when the radio wave from the base unit is far from the antenna of the base unit and cannot reach, only the owner is called.

In FIG. 2, an acceleration sensor 31 used in a navigation system of an automobile or the like is used in place of the step sensor 30 to detect acceleration and its direction, and the acceleration data and its direction are transmitted to the parent machine as movement data. Good.

[0040]

According to the call back device of the first aspect of the present invention, when the person having the master unit and the slave unit are close to each other, the electric field strength of the radio wave from the master unit exceeds the set value, and You can rest assured that radio waves will be transmitted from the aircraft to indicate safety. Further, when the electric field strength of the radio wave from the base unit becomes less than or equal to the set value because the two are too far apart from each other, the notification means of the handset can call out to the person or a person in the vicinity and call back the person holding the handset. Further, the monitor having the parent device can know that the infant or the old man having the child device is lost by the alarm means.

According to the call back device of the second aspect of the present invention, even if there are a plurality of slave units, the transmitting means of the master unit for selecting the slave units and transmitting the radio wave to be called can support a plurality of slave units.

According to the call-back device of the third aspect, the alarm means of the master unit is provided with the display unit for displaying the time when the alarm signal is detected and the time elapsed from this time, so that the slave unit has a predetermined function. You can find out when you have passed a point that is a distance away and how much time has passed since that point, which will be a clue when searching. According to the call back device of claim 4, when the notification means of the slave unit detects the notification signal, it reads the character information or voice information stored in advance and notifies the outside by characters or voice. It is possible to inform the people around it that they have been lost and encourage them to return to a predetermined place.

According to the call back device of the fifth aspect, when the person having the master unit and the slave unit are close to each other, the electric field strength of the radio wave from the master unit exceeds the set value, and the answerback radio wave from the slave unit is reached. Will be sent, so you can rest assured. Further, when the electric field strength of the radio wave from the base unit becomes less than or equal to the set value because the two are too far apart from each other, the notification means of the handset can call out to the person or a person in the vicinity and call back the person holding the handset.

Further, the monitor having the master can know that the infant or the old man having the slave is lost by the alarm means. Furthermore, the movement detection means counts the vibration due to walking from the time when the notification signal is detected and outputs it as movement data, and the transmission means of the handset transmits it, so that the observer starts from the time when the person with the handset becomes lost. You can know the movement status of.

According to the call back device of the sixth aspect, the movement detecting means detects the acceleration from the time when the notification signal is detected, and this is transmitted as movement data from the transmitting means of the slave unit.
It is possible to easily know whether the person with the child machine moved on foot or by bicycle or bus. According to the call back device of claim 7, since the transmission means of the slave unit increases the transmission output when detecting the notification signal, it is possible to reliably obtain the movement information and the position of the person holding the slave unit from a distant point. Can be easily detected.

[Brief description of drawings]

FIG. 1 is a block diagram of a master unit installed on the supervisor side.

FIG. 2 is a block diagram of a child device of an old man to be monitored.

FIG. 3 is a perspective view of a child device.

FIG. 4 is an explanatory diagram of use of the call back device according to the present invention.

FIG. 5 is a flowchart of a master unit.

FIG. 6 is a flowchart of a child device.

FIG. 7 is a perspective view in which a child device of another embodiment is attached to a hat.

[Explanation of symbols]

 1 master unit 2, 3, 4, 5 slave unit 5a, 27a speaker 5b, 11, 21 antenna 5c, 28 LED (informing means) 5d solar cell 12, 22 filter 13 receiving unit (receiving unit of parent unit) 13a level adjustment Device (reception means of base unit) 14 Transmission unit (transmission means of base unit) 15 CPU (alarm means) 16 Memory (alarm means) 17 Alarm device (alarm means) 18 Indicator (alarm means) (display means) 19 Clock (Alarm means) 23 Receiver (receiver means of the handset) 23a Level adjuster (receiver means of the handset) 24 Transmitter (transmitter means of the handset) 25 CPU (notification means) 26 Memory (notification means) 27 Amplifier ( Notifying means) 29 Display device (notifying means) 30 Step sensor (movement detecting means) 31 Acceleration sensor (movement detecting means)

Claims (7)

[Claims] 1. A slave unit comprising a receiving unit, a notifying unit and a transmitting unit, and a master unit comprising a receiving unit, an alarm unit and a transmitting unit, the receiving unit of the slave unit being an electric field of a received radio wave. When the intensity is less than or equal to the set value, it outputs a notification signal, and when the intensity is greater than or equal to the set value, it is a reception means that outputs a safety signal.The notification means of the slave unit is a notification means that notifies the outside when the notification signal is detected. Is a transmitting means that transmits a radio wave when a safety signal is detected, and the receiving means of the master unit is a receiving means that outputs an alarm signal when the electric field strength of the radio wave from the slave unit is below a set value. The call back device, wherein the alarm means of the machine is an alarm means for issuing an alarm when an alarm signal is detected. 2. The call back device according to claim 1, wherein the transmission means of the master unit is a transmission unit that transmits a radio wave for selecting and calling a plurality of slave units. 3. The call back according to claim 1, wherein the alarm means of the master unit is provided with a display means for displaying the time when the alarm signal is detected and / or the elapsed time from this time. apparatus. 4. The call back device according to claim 1, wherein the notification means of the slave unit is a notification means for reading and storing the stored character information and / or voice information when the notification signal is detected. 5. A slave unit comprising a receiving unit, a notifying unit, a transmitting unit and a movement detecting unit, and a master unit comprising a receiving unit, an alarm unit and a transmitting unit, wherein the receiving unit of the slave unit is a master unit. It is a receiving means that outputs a notification signal when the electric field strength of the radio wave from the device is below the set value and outputs a safety signal when the electric field strength is above the set value.The notification means of the slave unit notifies outside when the notification signal is detected. The movement detecting means is a movement detecting means that counts the vibration due to walking from the time when the notification signal is detected and outputs it as movement data, and the transmission means of the handset transmits the movement data after the safety signal is detected and the notification signal is detected. The receiving means of the parent device is a receiving means that demodulates the radio wave from the child device and outputs moving data and outputs an alarm signal when the electric field strength of the radio wave is less than or equal to a set value. The alarm means of the machine Recall device characterized in that it is a warning means for issuing an alarm when it detects an alarm signal and displays the data. 6. The recalling device according to claim 5, wherein the movement detecting means is a movement detecting means that detects the acceleration from the time when the notification signal is detected and outputs it as movement data. 7. The call back device according to claim 5, wherein the transmission means of the slave unit is a transmission means whose transmission output increases from the time when the notification signal is detected.