JPS6320071B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a data collection system that collects data using subscriber telephone lines.

In recent years, data transmission terminals (meter reading terminals) have been introduced from the data collection side, that is, the meter reading center side, using telephone lines.
An automatic meter reading system has been developed that calls the meter reading terminal and collects the data read by the meter reading terminal. The most important feature of this type of system is that it can call terminals and collect data without ringing the subscriber's telephone, that is, in a no-ringing manner.

The automatic meter reading system will be briefly described below with reference to FIG. That is, in response to a call command (dial operation) from the meter reading center 1, first the terminal station 3 on the meter reading center 1 side is connected via the telephone line 2, and then the terminal station 5 on the meter reading terminal side is connected via the trunk line 4. Connected. This terminal station 5 on the meter reading terminal side is a No Ringing Trunk (hereinafter referred to as No Ringing Trunk).
It is equipped with a trunk (abbreviated as NRT) 6 which generates a special calling signal that does not ring the bell of subscriber telephone 7. The special call signal generated by this NRT 6 is sent to a no-ringing network control unit (No Ringing NCU) via a telephone line 8.
(hereinafter abbreviated as NR-NCU) 9, and detected by this NR-NCU 9. This NR−
The NCU 9 detects the above-mentioned special call signal to send the code transmitter (hereinafter abbreviated as SOU) 1
The meter reading terminal 11 is activated via 0. here,
The SOU 10 has a function of receiving command information etc. from the meter reading center 1 and sending meter reading data obtained by the meter reading terminal 11 to the meter reading center 1.

Therefore, the subscriber telephone 7 and the meter reading terminal 11 are completely separated from each other when the meter reading center 1 calls, and as a result, the meter reading data can be read without causing the subscriber telephone 7 to ring, that is, without bothering the subscriber. can be collected.

However, in such a system, the SOU 10 and the meter reading terminal 11 are connected by a connection cable 12. For this reason, since the connection cable 12 and the connector are installed on the wall surface, problems such as detracting from the aesthetic appearance of houses and buildings have arisen. Further, depending on the location of the facility, the cost of this construction work may be extremely high, and there is a risk that the cost will be higher than the cost of the device itself. Furthermore, since the meter reading terminal 11 is generally composed of multiple types of meters such as a wattmeter, a gas meter, and a water meter, it is necessary to provide protection equipment against mutual interference between the meters, especially surges coming from the telephone line 8, power lines, etc. There is a need. Also, each meter and
When performing maintenance on SOU10, the problem of demarcation of responsibility sometimes occurred when multiple operators were involved.

The present invention has been made focusing on the above circumstances,
The purpose of this is to eliminate the need for connection work between the SOU and data transmission terminals, eliminate mutual interference between each terminal when there are multiple data transmission terminals, and prevent erroneous interference from other data transmission terminals in the vicinity. An object of the present invention is to provide a data collection system that can always establish an accurate wireless connection without having to call again.

Hereinafter, the present invention will be described with reference to an embodiment shown in the drawings. In this embodiment, an automatic meter reading system is applied, and the same parts as in FIG. 1 will be described with the same reference numerals.

FIG. 2 is a block diagram of the main parts of the data collection system according to the present invention, and 9 in the figure indicates a no-ringing network control unit (NR-NCU). This NR−
The NCU 9 includes an off-hook detection circuit 21 for detecting off-hook of the subscriber telephone 7 and a no-ringing call signal (NR call signal) detection circuit 22.
It is equipped with several detection circuits. This NR call signal detection circuit 22 is a no-ringing trunk (NRT)
6 through the telephone line 8 is detected. This NR call signal has a special signal format and frequency that does not cause the bell of subscriber telephone set 7 to ring. Also, NR−NCU
9 is a switch circuit 23 consisting of a semiconductor switch.
and a stabilized power supply circuit 24. The switch circuit 23 is the NR call signal detection circuit 22.
The telephone line 8 is electrically connected to a connection device 30, which will be described later, only during the period when the NR call signal is being detected, that is, during the meter reading data collection period. Further, the switch circuit 23 operates when the off-hook is detected by the off-hook detection circuit 21 and when no data collection or telephone conversation is being performed.
The telephone line 8 and the connection device 30 are disconnected. On the other hand, when collecting meter reading data, the stabilized power supply circuit 24 stabilizes the power output supplied from the station power supply of the terminal station (FIG. 1 5) via the telephone line 8 and the switch circuit 23, and then 3
It is applied to 0. Therefore, the connection device 30 can only operate when collecting meter reading data.
Moreover, it operates with a constant power output that eliminates fluctuations caused by line conditions such as line length and wire diameter of the telephone line 8.

By the way, the connection device 30 includes a modulation/demodulation circuit 31, a first transmission control circuit 32, and a wireless transceiver 33, which together with the modulation/demodulation circuit 31 constitute the SOU 10. The modulation/demodulation circuit 31 demodulates the AC signal control information from the meter reading center 1 into pulse code control information, modulates the coded meter reading data derived from the first transmission control circuit 32 (described later), and sends it to the telephone line 8. It is to be sent to. Here, the control information includes call information, meter reading data transmission command information, and the like.

The first transmission control circuit 32 also includes a control section A that interfaces with the meter reading center 1 side, and a control section B that interfaces with the wireless terminal 40 side, which will be described later. One control unit A performs erroneous control on the control information from the meter reading center 1, then recognizes it and returns the response status to the meter reading center 1, and also temporarily stores the meter reading data from the control unit B and sequentially transmits it at a predetermined timing. It is sent to the meter reading center 1. On the other hand, control section B
transmits the control information from the control unit A to the wireless terminal 40.
It also has a function of temporarily storing the meter reading data from the wireless terminal 40 and sending it to the control unit A after error control.

On the other hand, the wireless terminal 40 includes a meter reading terminal 11 that obtains meter reading data, and a connecting device 3 between this meter reading terminal 11 and the connecting device 3.
0, a second transmission control circuit 41 that controls transmission of control information and meter reading data, and a wireless transmitter/receiver 42. Wireless terminal 40
is equipped with a single type or multiple types of meters 43 such as a power meter, a gas meter, and a water meter, and the measured values of these meters 43 are detected by a sensor 44 and amplified and A-D converted by a conversion circuit 45. It is stored in the memory 46 later.

Further, the second transmission control circuit 41 performs error control on the control information sent from the connection circuit 30 and then identifies it to determine whether or not it has been called. Further, the second transmission control circuit 41 reads meter reading data from the memory 46 of the meter reading terminal 11 in accordance with control information from the meter reading center 1, assembles it into a predetermined format, and sends it to the device 30.

Now, the meter reading terminal 11 of such a wireless terminal 40
(To be precise, the second transmission control circuit 41) and the SOU 10 of the connection device 30 transfer control information and meter reading data through a pair of wireless transmission/reception devices installed in both the wireless terminal 40 and the connection device 30, respectively. This is done by machines 33 and 42. That is, the wireless transceiver 33 modulates the control information from the first transmission control circuit 32 and then transmits it to the wireless line 50 via the antenna 33a, and demodulates the meter reading data that has arrived via the wireless line 50. It is then supplied to the first transmission control circuit 32. On the other hand, the wireless transceiver 42
receives the control information arriving via the wireless line 50 with the antenna 42a, then demodulates it and transmits it to the second
The meter reading data from the second transmission control circuit 41 is modulated and sent to the wireless line 50. At this time, the electric field strength sent to the wireless line 50 is determined to be so weak that it is not subject to the regulations of the Radio Law. Therefore, it is not subject to any special restrictions such as the frequency band used, and can be easily implemented.

Note that as a power source for the wireless terminal 40, a local battery such as a dry battery or a solar battery (not shown) is applied.

Next, the operation of the data collection system having such a configuration will be explained with reference to FIGS. 3 to 6, respectively. In addition, Fig. 3, Fig. 4, and Fig. 5 a are
It shows the voltage appearing on the telephone line 8 in each operating state.

First, when calling the subscriber telephone set 7 of this system from another subscriber telephone set, a calling signal as shown in FIG. . This calling signal has an effective value of 75 V and a frequency of 16 Hz. In the figure, O indicates the calling period, P indicates the talking period, and A and B indicate off-hook and on-hook, respectively. Here, even if a call signal is received and a call is made, the switch circuit 23 of the NR-NCU 9 remains open, so the connection device 30 remains inactive. Therefore, the operation of collecting meter reading data is not performed, and a normal telephone call is made using the subscriber telephone set 7.

Furthermore, when making a call from the subscriber telephone set 7 of this system, the switch circuit 23 remains open during the period from off-set to on-set as shown in FIG. does not affect calls in any way. Note that Q, R, and P in FIG. 4 indicate a dial operation period, a connection period, and a call period, respectively.

Next, a case will be described in which the meter reading center 1 calls the wireless terminal 40 to collect meter reading data. When the line between the meter reading center 1 and the NRT 6 of the terminal station 5 is established by a call from the meter reading center 1, the NRT 6 calls the telephone line 8 to the NR-NCU 9.
The NR call signal is sent via the NR call signal. This NR call signal is detected by the NR call signal detection circuit 22 of NR-NCU9.
When detected, the switch circuit 23 connects the telephone line 8 and the connection circuit 30, and the output of the station power supply is applied to the connection device 30 via the stabilized power supply circuit 24. As a result, the connection device 30 starts. At this time, the NR calling signal has a slow rise that does not cause the subscriber telephone 7 to ring, as shown in FIG. 5a, and has a relatively high calling frequency of about 2 KHz. For this reason,
The subscriber telephone 7 does not ring at all, so the subscriber is not disturbed.

In this way, when the connection device 30 is activated, the first
The transmission control circuit 32 returns response information to the meter reading center 1, and upon receiving this, transfers the control information sent from the meter reading center 1 to the wireless terminal 40 as shown in FIG. 5b. At this time, the control information is transferred via the wireless line 5 by the wireless transceivers 33 and 42.
This is done via 0.

The wireless terminal 40 uses the received control information as a second
transmission control circuit 41, and when the identification result is a call to itself, the meter reading terminal 11
The meter reading data obtained is assembled into a predetermined format by the second transmission control circuit 41 and transferred to the connection device 30 as shown in FIG. 5c. At this time as well, the meter reading data is transferred wirelessly. In this way, the meter reading data transferred from the wireless terminal 40 to the connection device 30 is transmitted to the meter reading center 1 via the telephone line 8 etc. by the first transmission control circuit 32 and the modulation/demodulation circuit 31. In FIGS. 5a to 5c, S indicates a no-ringing call period, T indicates a transmission period of control information and meter reading data, and C indicates a response time.

Here, if off-hook of subscriber telephone 7 is detected during the transmission period of meter reading data, switch circuit 23 is opened at that moment and electrical connection between telephone line 8, connection device 30 and wireless terminal 40 is established. The connection device 30 is then disconnected, and the connection device 30 becomes inactive. As a result, the terminal station 5 stops the meter reading data transmission mode and returns to the telephone call mode of the subscriber telephone set 7. FIG. 6 shows this operation. In the figure, T,
P and I represent the meter reading data transmission period, call period, and off-hook, respectively.

Furthermore, if a call occurs from another subscriber during the transmission period of meter reading data, a signal indicating that it is "busy" is sent from the terminal station 5 to the calling party, and the meter reading center 1 continues. Collect meter reading data.

As described above, according to the data collection system of this embodiment, the wireless transmitter/receiver 33 is provided on the SOU 10 side, and the wireless transmitter/receiver 42 is provided on the meter reading terminal 11 side, and control information is transmitted by each of the wireless transmitters 33 and 42. and meter reading data are transferred, so unlike the conventional system, the connection cable 1
2, that is, it is not necessary to connect the SOU 10 and the meter reading terminal 11 using a wired line. As a result, there is no need for construction work on cable line facilities, there is no need to worry about spoiling the aesthetics of the house or building, and it is also possible to change the connecting line extremely easily. Further, by using a wireless line instead of a wired line, it is possible to prevent mutual interference between the meters 43 and prevent the entire system from becoming inoperable. Furthermore, for example, NR-NCU can be installed at public telephones.
9 and the connection device 30, it is possible to collect meter reading data from customers who do not have subscriber telephones 7, and there is no need to install directly or self-operated lines in communal buildings, factories, housing complexes, etc. Meter reading data can be collected.

Furthermore, in this embodiment, when the wireless terminal 40 is driven by a solar battery, it is possible to save energy. Furthermore, since the connecting device 30 only needs to be operated during the time when meter reading data is transmitted, there is no increase in power consumption and there is an advantage that the local power source can be used as is.

Note that the present invention is not limited to the above embodiments. For example, a plurality of wireless terminals 40 may be selectively connected to one connection device 30 to collect meter reading data. In addition, the second transmission control circuit 4 assembles the meter reading data format.
The first transmission control circuit 32 may be used instead of the first transmission control circuit 1. Furthermore, it can be applied not only to automatic meter reading, but also to terminal-to-terminal data communication, image communication, telemanagement, etc. Further, as a power source for the wireless terminal 40, a general battery (battery) may be used instead of a solar battery. In addition, the functions and configurations of the NR-NCU, SOU, and meter reading terminal 11 can be modified in various ways without departing from the gist of the present invention.

As described in detail above, according to the present invention, the connection between the SOU and the data terminal device is performed wirelessly, thereby simplifying the connection work between the SOU and the data transmission terminal and reducing the installation cost. At the same time, it is possible to prevent the aesthetic appearance of the building from being spoiled, and when there is a plurality of data transmissions, it is possible to prevent mutual interference between terminals and perform stable data collection. In addition, the wireless terminal side performs error control to identify the control information sent from the SOU side via the wireless line, and from this identification result determines whether or not the call is to itself. By sending meter reading data from data transmission terminals, it is possible to always establish accurate wireless connections without accidentally calling other nearby data transmission terminals, thereby providing a highly reliable system. can do.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional data collection system, FIG. 2 is a configuration diagram of main parts of a data collection system according to an embodiment of the present invention, and FIGS. 3 to 6 are for explaining the operation of the above embodiment. It is a signal waveform diagram for use. 1...meter reading center, 5...terminal office, 6...no-ringing trunk (NRT), 7...subscriber telephone,
8...Telephone line, 9...NR-NCU, 10...
SOU, 11...meter reading terminal, 30...connection device,
31...Modulation/demodulation circuit, 32...First transmission control circuit, 33, 42...Radio transceiver, 40...Wireless terminal, 41...Second transmission control circuit, 50...Radio line.

Claims (1)

[Claims] 1. In a data collection system in which the data collection side calls a data transmission terminal in a no-ringing method using a subscriber telephone line to collect data,
a no-ringing network control device that detects a call from the data collection side; a connection device that is electrically connected to the subscriber telephone line only during the call detection period of the no-ringing network control device; and the connection device that includes the data transmission terminal. a wireless terminal connected to the wireless terminal via a wireless line, and the connecting device includes:
The wireless terminal includes means for transmitting control information from the data collection side to the wireless terminal via the wireless line, and the wireless terminal performs error control on the control information that arrives from the connecting device via the wireless line, and then identifies the control information. A means for determining whether or not the call is for the self based on the identification result, and a means for assembling the meter reading data obtained by the data transmission terminal in a predetermined format when it is determined by this means that the call is for the self, and then connecting the 1. A data collection system comprising: means for transmitting data to a device via a wireless line.