JPS6251018B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention collects data using subscriber telephone lines, and particularly relates to a data collection device that operates to always give priority to telephone calls.

One method of remotely and centrally reading the consumption of electricity, gas, water, etc. is to collect data using telephone lines. The following methods are considered as specific data collection methods.

(1) A method of connecting a telephone line and a data terminal using a network control device; with this method, it is necessary to manually identify and switch between telephone and data at the terminal, whether it is an outgoing call or an incoming call. This is a nuisance for telephone subscribers, and if you make a mistake, you may miss an important call.

(2) In order to eliminate the disadvantages of the above method, the telephone and data terminal are always connected in parallel to the telephone line, and when a call is received, a 16Hz ringing signal is sent from the exchange, and the telephone bell is to notify the subscriber of an incoming call. On the other hand, in the case of data, calls arrive at data terminals using a data call signal system in which the exchange has a function that does not ring telephones with frequencies other than 16Hz.

Method (2) is superior to method (1) in that it does not impose a burden on telephone subscribers, but it requires some modification of the exchange equipment and is the best method for telephone exchange. From the point of view of the switching system, which is designed to be as efficient as possible, there are many points that need to be considered in terms of operation and maintenance. For example, if a call is received from another subscriber while the meter is being read, a busy tone is sent to the other subscriber. There are many types of exchanges, such as A-type, H-type, and XB-type electronic exchanges, and so far no practical system has been found for any of them.

The present invention aims to eliminate these drawbacks by modifying the exchange or by creating a special connection between the exchange and the exchange, such as by communicating between the data collection device and the exchange using a control line other than the telephone line (for example, C line). The purpose of the present invention is to provide a data collection device that does not impose any burden on subscribers, such as the need for communication or, for example, the introduction of special signaling systems.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a data terminal, and 2 is a telephone set, which are connected to subscriber side terminals L ₁ and L ₂ of a telephone line 3, respectively. A relay E is inserted between this terminal L ₂ and the telephone 2, and its break contacts e ₁ , e ₂
are interposed between the subscriber side terminals L ₁ and L ₂ and the data terminal internal circuit 1a.

Reference numeral 4 denotes a data collection device installed at a telephone office, and is provided between terminals A and B of the telephone line 3 and terminals a and b on the exchange side.

That is, a varistor VR1 and a capacitor _C1 are interposed and connected in parallel between the terminals A and A, and a contact _c1 of a relay C, which will be described later, is provided in parallel with the varistor _VR1 and the capacitor C1. In addition, capacitors C ₂ and C ₃ are connected to terminals A and B, respectively, via contacts c ₂ and c ₃ of relay C, and the other ends of these capacitors C ₂ and C ₃ are connected to contacts b _{1 and 3} of relay B, which will be described later.
b ₂ to a data transmission modulation/demodulation device (not shown) as a data collection main device. Further, photocouplers PC ₁ and PC ₂ are connected in parallel with contacts c ₁ and c ₃ of relay C and the varistor VR1. The photocouplers PC ₁ and PC ₂ are composed of a so-called light-emitting diode and a phototransistor, with the light-emitting diode side serving as an input side, and the phototransistor side serving as an output side. The photocouplers PC ₁ and PC ₂ are connected to the varistor VR1 with their input sides having opposite polarities, and a resistor R ₁ is connected between one end of the input side and the varistor VR1. Further, a resistor R ₂ , a diode D ₁ , a Zener diode ZD ₁ , a photocoupler PC ₃ , and relay contacts c ₁ and c ₂ are interposed and connected in series between terminals a and b. Furthermore, relays B and C are provided within the data collection device 4, and one ends of these relays B and C are connected to a power source.

The varistor VR1 and resistor _R1 function as surge protection and current limiting, respectively, and _C1 acts as the varistor VR1.
This reduces the terminal impedance of
Photo couplers PC ₁ and PC ₂ are for loop current detection.
Photocoupler PC ₃ is for detecting incoming calls.

In addition, diode D ₁ is used to match the polarity to the telephone line voltage at the time of incoming calls, Zener diode ZD ₁ is designed to have a threshold slightly lower than the telephone line voltage (48V), and resistor R ₂ is for current limiting, and capacitors C ₂ and C ₃ are for direct current blocking.

Reference numeral 5 is an example of a relay circuit and a trunk circuit of an exchange, and is shown for the purpose of explaining operations such as data collection and telephone reception.

In such a configuration, for convenience, the operations of the relay circuit and the trunk circuit will be explained before explaining the data collection device 4. First, in normal times, the relay circuit and trunk circuit 5 are connected to +earth air - -48V - relay L winding - contact c ₀₁ - terminal a - telephone line, subscriber equipment - terminal b - contact c ₀₂ - + earth air. A starting circuit is configured by the route, terminals a, b → terminals A, B → terminals L ₂ , L ₁
-48V appears, but no loop current is flowing.

Next, there is an off-hook of the telephone, a loop current flows, and when loop activation is detected by relay L, the office line is connected to the input side of the ICT (incoming trunk) and dial information is received by a circuit not shown. A loop current is supplied from relay A from the end of the dial until the end of the call. Furthermore, when the other party answers, the polarity of the telephone line is reversed.

For incoming calls, the telephone line is connected to the ICT from the subscriber circuit.
is connected to the output side of the telephone, and the ringing signal to the telephone is
+ Earth - 16Hz - Relay F winding - Contact g ₀ - Terminal a
-Terminal L ₂ -Telephone -Terminal L ₁ -Terminal b-Contact g ₂ -Resistance--48V-+Earth air route sent to terminal a,
b appears a signal in which +48V, which is in the opposite direction to the normal -48V, and an intermittent calling signal (16Hz) are superimposed. When the telephone rings and the subscriber answers, a loop current flows into the relay F winding, and the ringing circuit is disconnected (ring tripped) by contacts g ₀ and g ₂ of relay G (not shown), and the loop current flows through the relay F. D, a communication path is established with the other subscriber, and the communication path is maintained from then on until the end of the call. After the ring trip occurs, the polarity of the local power source appearing at terminals a and b returns to its original state.

Next, the operation of the data collection device 4 will be explained based on the operation of the relay circuit and trunk circuit of the exchange.

First of all, when both telephone and data collection are in normal condition, data terminal 1, telephone 2 in Figure 1,
The telephone line 3 and data collection device 4 are each in the state shown in the figure, and the relay circuit and trunk circuit 5 have subscriber circuits connected to terminals a and b. However, since the loop is not closed, the relay does not operate, and no dial tone is sent to the telephone line, and terminals a, b → A, B
→Only -48V appears in L ₂ and L ₁ .

Second, if data collection is to be started from this state, a signal is given to the control terminal (CONT) to drive relay C in response to a command from, for example, a central device (not shown). Then, the contacts c ₁ , c ₂ , c ₃ of this relay C
moves, and photocouplers PC ₁ , PC ₂ , and PC ₃ are inserted into the telephone line. If the telephone is not in use, no output will appear at the output terminals S ₁ , S ₂ , and S ₃ of the photo couplers PC ₁ , PC ₂ , and PC ₃ (open state). After confirming this, give a signal to the relay B side of the control terminal (CONT) to drive relay B, and connect the modem of the data acquisition device.
It connects to the telephone line at b ₁ and b ₂ and starts data communication with the internal circuit 1a of the data terminal 1. During this time, relay C remains activated and the photo coupler
Insert PC ₁ , PC ₂ , and PC ₃ into the telephone line. In addition to the terminal, the telephone and the subscriber circuit are connected in parallel as loads on the modem, but the telephone is turned off by the switch, so it has no effect. The subscriber circuit is still less affected by the high impedance of the relay, and since the loop is not activated, no tones are sent out and there is no interference with data collection. When data collection is completed, relays B and C are deactivated and the contacts are restored to the state shown in the figure, so there will be no problem in using the telephone from now on. Even if the contact _c1 should have a contact failure, if the loop is closed, the loop current will flow through the varistor VR1. If the voltage of this varistor VR1 is selected to be several volts, the loss of the local power supply will be small and the impedance will be very small, so that it will not interfere with the operation of the telephone.
Capacitor _C1 serves to lower the AC impedance.

Next, when relay C is driven to start data collection, if the telephone is in some kind of usage state, an output (continuity) will appear on one of terminals S ₁ , S ₂ , or S ₃ , and relay B will be driven. interrupts the signal supply to the control terminal (CONT) that is being attempted. Then, monitor the telephone line while keeping relay C driven, or open relay C and then drive relay C again after a certain amount of time has passed to check the state of the telephone line.

The appearance of the output to terminals S ₁ , S ₂ , and S ₃ differs depending on the state of the telephone at that time. First, when a telephone subscriber goes off-hook to make a call, it is connected to the subscriber's circuit, and a loop current flows through the photocoupler _PC1 , and an output appears at the terminal _S1 . At this time, a loop current flows due to the off-hook, which causes relay E to operate and contacts e ₁ and e ₂ to turn off, thereby disconnecting the data terminal internal circuit 1a from the office line.
Next, after the call has started, it is connected to relay A of the ICT and similarly output to terminal _S1 . Furthermore, when the other party answers and a call begins, the polarity of the loop current is reversed, so a loop current flows through the photocoupler PC ₂ , and an output appears at the terminal S ₂ . In the case of an incoming call, a 16Hz ringing signal is superimposed on +48V and applied to terminals a and b via ICT relay F. This is applied to the photocoupler PC ₃ via the Zener diode ZD ₁ and conducts, and an output appears at the terminal S ₃ . At the same time, the photocoupler alternates every half wave of 16Hz.
Current also flows through PC ₁ and PC ₂ , and the terminals synchronize with this.
Outputs also appear in S ₁ and S ₂ . In the case of an incoming call, a loop current flows from relay D of the ICT via photocoupler PC ₁ and is output to terminal S ₁ .

In this way, detection is possible in any operating state of telephone use.

Fourthly, if the telephone line happens to be in use during data collection, it can be detected as in the third case, so relays B and C are immediately deactivated, the telephone line is returned to the telephone use state, and the subscriber does not give any special reaction and does not cause any trouble.

In this regard, conventionally, when data and phone calls collide, when a call is received, a busy tone is returned to the other subscriber so that the subscriber can call again, and when the call is made, the user goes off-hook, and the busy tone is immediately displayed instead of the dial tone. In some cases, the caller would have to put down the handset, go off-hook again, and then make the call.

In contrast, the present invention does not impose any burden on telephone subscribers, nor does it affect traffic.
It is possible to collect data using the time when the phone is not in use, and the principle of giving priority to the phone can be observed.

FIG. 2 shows another embodiment of the present invention, in which the data terminal is supplied with DC power from the collecting device. The exchange side is the same as that shown in FIG. 1, so it is omitted.

To explain only the parts in FIG. 2 that are different from the example in FIG. 1, 1b is the carrier wave generator of the data terminal 1, and the contact point
A Zener diode ZD2 diode D2 is connected in series with _e2 .

On the other hand, in the data collection device 4, T is a transformer for coupling and current supply, and a battery B is connected to the middle point of the secondary side.
1 and B2 are connected in series. B1 is the normal -
48V battery, B ₂ is +50V booster battery.

Contacts b ₁ and b ₂ of relay B serve as relay contacts for switching between connecting the line from the subscriber to the exchange or to the modem (MODEM) of the data collection device.

Next, the operation will be explained with reference to FIG. Figure 3 shows _the line voltage generated at terminals L ₁ and L ₂ of the terminal.
This shows the case when viewed as a voltage change.

Furthermore, Figure 3a shows the voltage waveform in the case of a telephone call, in which the polarity of the -48V local power supply voltage is reversed to +48V upon receipt of a call, and changes in response to the 16Hz ringing signal.
The response (off-hook) causes a voltage drop in the loop, resulting in a call state, and the off-hook causes a voltage drop of -48V.
This indicates a return to normal conditions.

Figure 3b shows the voltage waveform when making a telephone call, -
The figure shows that 48V changes due to off-hook and becomes an intermittent voltage according to the dial pulse, and when connected to the other party's terminal, the voltage polarity is reversed, the call state is established, and it returns to -48V due to off-hook.

To explain this based on the premise of performing such incoming and outgoing operations, first of all, when the telephone and data collection are in normal condition, the relay contacts of each part in Fig. 2 are in the positions shown, and the exchange side is As in Figure 1, it is connected to the subscriber circuit LR. In this state, as explained above in Figure 1, -48V is applied to L ₁ and L ₂ .
only appears. The DC power for the data terminal internal circuit 1b is supplied from the data acquisition device 4, but the voltage regulator diode ZD2 is inserted to set its threshold voltage to 50V, and the polarity is added using the diode _D2 , so the voltage is +48V. is terminal L ₁ ,
Even if added to L ₂ , it will not be activated.

If you want to start data collection from this state as shown in Fig. 2, as mentioned in the explanation of Fig. 1, first check the state of the station line by driving relay C, and then
When it is confirmed that there is no output at S ₁ , S ₂ , S ₃ , relay B is further driven, contacts b ₁ and b ₂ are switched, and battery B ₂ (50V) is connected via transformer T. and battery
The added voltage of 48V of _B1 is applied to the data terminal and internal circuit 1a, and at the same time the data terminal internal circuit 1a is activated, the current for operation of this data terminal internal circuit 1a is also supplied, and the carrier wave generator 1b immediately sends the data to the collecting device 4. Send carrier waves continuously. At this time, the voltage at terminal _L2 becomes as shown in FIG. 3C.

In addition, the carrier wave is the modulation/demodulation equipment (MODEM) of the terminal.
It goes without saying that a carrier wave for data transmitted from a carrier wave may also be used. In this way, data communication is performed between the data terminal 1 and the data collection device 4.
When data collection is completed, relays B and C are deactivated and the telephone line is restored to its normal state.

Third, when starting data collection, the telephone line is checked and the telephone is found to be in use, the operation is similar to that described in FIG.

Fourth, when there is an off-hook for making a call during data collection, we are considering a method of detecting the off-hook by detecting that a loop current has flowed through the terminal, that is, by identifying an increase in the total loop current. However, the telephone lines in No. 3 have different lengths and are difficult to identify, and other measures are required. Now, when the telephone is off-hook, the terminal voltage of L ₁ and L ₂ becomes less than 50V due to its internal resistance as shown in Figure 3d, the Zener diode ZD ₂ becomes non-conducting, and the loop current is entirely limited to the telephone. flow, relay E operates,
The data terminal 1a is disconnected at contacts e ₁ and e ₂ . At the same time, the carrier wave transmission also stops, so the data collection device 4
This interruption of the carrier wave is regarded as a request to make a telephone call, and the telephone line is immediately restored and contacts b ₁ and b ₂ are reconnected to the exchange side to ensure that there is no problem with the telephone call.

Furthermore, as another embodiment, it goes without saying that the present invention is also useful in cases where a rechargeable battery is placed in the terminal and is constantly or appropriately charged by a collection device.

In this way, even if the terminal relies on the central power supply for the power required, it is possible to give complete priority to calls and prevent deterioration of subscriber service.

In each of the embodiments described above, the means for detecting the operating mode of the telephone on the telephone line was configured to be connected only when collecting data. , this may be configured to be always connected.

As described above, according to the present invention, when collecting data using the subscriber telephone line that exists for telephone calls, there is no need for modification of the exchange or special lead-out circuit from the exchange. It can be implemented, can be applied to any type of exchange, and can detect any operating mode of a telephone line, such as outgoing, incoming, or ringing, and always gives priority to the telephone even when tested from a central office test stand. It is possible to provide a data collection device that operates as shown in FIG.

[Brief explanation of the drawing]

Fig. 1 is a wiring diagram showing a data collection device according to one embodiment of the present invention, Fig. 2 is a wiring diagram showing another embodiment of the invention, and Fig. 3 is a diagram showing a terminal on the subscriber side in Fig. 2. It is a voltage waveform diagram. DESCRIPTION OF SYMBOLS 1...Data collection terminal, 2...Telephone, 3...Subscription telephone line, 4...Data collection device, 5...Part of the internal circuit of the telephone exchange.

Claims (1)

[Claims] 1 A data collection device that is installed at a telephone office and collects data from a data terminal using a subscriber telephone line when the telephone is not in use, and the connection between the device and the exchange is only through the subscriber telephone line. The telephone is inserted into the subscriber telephone line between the telephone and data terminal and the exchange, and depending on the status of the subscriber telephone line, the telephone makes outgoing calls, makes calls, receives calls to the telephone, and other times when the telephone is not in use. If a conflict between the telephone and the data collection device is detected by the means, priority is given to the telephone at all times, and the data collection device is disconnected during normal times and when the telephone is in use. data collection device.