KR900007703B1 - Tone-respousive circuit for ac tivating an instrumentality interfacing system - Google Patents

Abstract

An activation circuit and an input device communicates with the line and is adapted to receive operating currents and an activation signal from the line. A capacitor (13) stores current received from the line and a circuit limits the received current to less than that required to operate the interrogating system. A circuit detects the storage of a selected amount of current, and provides a triggering signal on such detection. A signal detector (18) causes activation of the interrogation system on detecting the presence of the activation signal on the line. A switching device (17) connecting the capacitor and signal detector for operating the signal detector in response to the triggering signal.

Description

Beep response circuit for starting the instrument connection system

1 is a block diagram showing a beep response circuit of the present invention.

FIG. 2 is a timing chart for explaining a waveform indicating the operation of the circuit shown in FIG.

3 to 5 are circuit diagrams incorporating the block diagram shown in FIG.

6 to 8 are schematic diagrams showing an appropriate circuit configuration incorporating the block diagram shown in FIG.

The present invention generally relates to a system for accessing various remote instruments, in particular a circuit capable of selectively starting the instrument and a unit functionally connectable in response to the detected beep.

Recently, great interest has been paid to the development of systems for various interrogators, for example, interrogating remote instruments that can obtain the necessary information without having to go to the remote area where they are installed. Have. A common form of remote location includes the detection of an alert indicating that the device in question is receiving a change in a particular state. This state change means various alarm conditions such as fire, illegal intrusion, measurement of specific parameter, deviation from specific reference value. Another common form of remote interrogation involves accessing instruments and other information gathering devices. This may include access to devices that can monitor any of a number of parameters such as flow rate, temperature and pressure, as well as electricity meters, gas meters and others.

In general, this kind of interlocation is achieved by sending one beeper or group of tones to the instrument being accessed, and reading one or more parameters monitored by the instrument and transmitting it to the interrogation signal source. Normally, this operation occurs over the telephone line, since it eliminates the need to separate the line between the interrogation signal source and the remote instrument. However, this method has the drawback of having to include multiple telephone companies and having to follow these actions in rules imposed by different telephone companies.

One such rule, to which the present invention is primarily concerned, relates to using current from a telephone line to operate an associated device. Several rules place specific restrictions on the amount of power that can be drawn from the telephone line, which eliminates the unacceptable obstacles to the telephone service and ensures that fault detection circuits, which many telephone companies have used in the past, can operate correctly.

When the telephone line is in the service state (so-called off-hook state), it is usually possible to draw enough current from the telephone line to operate the remote monitor.

However, this needs to continue to occupy the telephone line being accessed during this period, and it is unacceptable and often unusable for this condition to occur as the call or data communication is affected by such ancillary equipment. Done. Even when the telephone line is not used (so-called on-hook state), a generally well-known rule strictly limits the amount of current drawn from the telephone line, usually a few microamps, which is usually the most remote Insufficient to operate the monitoring device. In most cases, the remote monitoring value is part of the service requested or part of the service booked by the subscriber. In the case of providing this type of service, the subscriber will benefit from or expect to perform such service services. Thus, the company providing this service is usually free to use the subscriber's powerline, which avoids being locked into the aforementioned limitations.

However, in the case of connection with a particular type of instrument measuring device, the remote monitoring device is operated for the convenience of use or the convenience of another third party, not for the convenience of the subscriber who owns the house in which the remote instrument is installed. Since this operation is for the convenience of the third party, not for the convenience of the subscriber, this method prohibits drawing out power from the subscriber's house to such a system. Thus, the only power source that can be drawn to operate the remote monitoring device is to enable communication in the remote period interleaved with the interrogation system, and to be a telephone line under the constraints described above. In addition, calling a subscriber's phone has limited access to the telephone line (typically off-peak), and calls from the subscriber's phone should be avoided, so typical call monitors cannot receive enough current to operate.

Therefore, it is desirable to develop a means to operate an interrogation system that can draw the required current from the communicable telephone line, which eliminates the need to draw current from a house equipped with a remote instrument, and It can be operated without drawing more current than the rule allows.

It is therefore a primary object of the present invention to provide an improved system capable of interrogating remotely using telephone line means.

Another object of the present invention is to provide a system capable of remotely interrogating without drawing power from a house equipped with a remote instrument using a telephone line means.

It is still another object of the present invention to provide a system capable of remotely interrogating power in the form of drawing power from a telephone line serving a system.

It is still another object of the present invention to provide a system capable of remotely interrogating operating power from a telephone line serving a system without exceeding the maximum current specified in the current rules.

It is still another object of the present invention to provide a system which provides the above advantages but is simple, reliable in operation and remotely interleaved.

These and other objects can be basically achieved by the present invention, which provides a beep response circuit that operates in accordance with a set duty cycle, wherein during most of each cycle the current is at a rate within the range allowed by the current phone rules. A beep detection circuit that draws from the telephone line serving the system and charges the capacitor over a sufficient time, and at the remainder of each cycle, the charge charged to the capacitor detects whether the remote instrument is receiving interrogation. It is used to operate simply.

If no such beep is detected, the circuit continues its periodic operation as previously described. In addition, when a beep indicating the desired interrogation is detected, the beep response circuit activates the monitoring unit used to monitor the instrument. When the monitoring unit is activated, the telephone line serving the system is in a call state, drawing enough power from the telephone line to operate simply in the desired form and preventing other calls from entering the line so as not to interfere with processing. .

After the desired information is transmitted to the signal source of the interrogation signal, the remote monitoring unit is in an inoperative state, and the beep response circuit enters the initial state to perform the intermittent operation as described above.

The beep response circuit according to the present invention will be described according to the detailed description and the accompanying drawings.

While specific examples of the invention are shown in the drawings and the following description also illustrates these specific examples, these descriptions are not intended to limit the scope of the invention as defined in the appended claims.

1 shows a beep response circuit according to the present invention. The beep response circuit 1 receives an input signal from the telephone line 2 available by being coupled to the tip 3 and the ring 4 terminal hanging on the telephone line 2 according to a known method. The resistors 4 and 5 represent a load on the telephone line 2 and are combined with a full-wave rectifier 7 which operates as a polarity correction means to supply an appropriate current to the terminal 8. The arrester 9 forms a bridge with the resistors 5 and 6 to protect the circuit 1 from external conditions including the telephone line 2. The capacitor 10 allows the circuit 1 to be separated from the transient.

The current generated at the terminal 8 is supplied to the current source subcircuit 11, which supplies the fixed current accurately adjusted to the line 12 irrespective of the change in voltage generated at the terminal 8. . The current source subcircuit 11 is configured to limit the current coming from the terminal 8 to a value specified in the rules of the current telephone company. The nature of this limitation is described next. The capacitor 13 grounds the output 12 of the current source subcircuit 11 so that a specific voltage shift appears at the terminal 14, which is a regulated current supplied to the output 12 of the current source subcircuit 11. And the capacity of the capacitor 13.

The terminal 14 is also grounded by the charging voltage comparator subcircuit 15. The charged voltage comparator subcircuit 15 is configured to monitor when the voltage across the capacitor 13 reaches a specific trigger voltage to sense the voltage shift seen at terminal 14. When this trigger voltage is detected, the charging voltage comparator subcircuit 15 generates an output at a terminal 16 which starts (crosses) the switch 17 which is open in a normal state. In this way, the voltage generated at the terminal 14 is connected to the beep detection subcircuit 18 which appears at the terminal 14 via the switch 17 and responds to the voltage shift.

This allows the beep detection subcircuit 18 to immediately find the beep indicating the desired interrogation. As a result, the capacitor 19 serves to connect to the input 20 of the beep detection subcircuit 18 through the circuit 1. If an appropriate beep is detected, the beep detection subcircuit 18 supplies an output signal to the output 21, which is used to start the interrogation process as described in detail later. If a proper beep is not detected, the low level voltage present at terminal 14 eventually removes output line 16 of subcircuit 15, which is a charging voltage comparison circuit, from switch 17, thereby allowing switch 17 to operate normally. Return to the open state and return the circuit (1) to its original state. In this case, the capacitor 13 is charged again until the trigger voltage is reached, and this state serves to periodically repeat the above-described process until the required beep is detected.

Thus, the circuit 1 serves to periodically check the telephone line 2 to which the circuit 1 is coupled in order to determine whether a beep indicating the required interrogation has been received. These periodic checks include triggering voltages (e.g., 4.5 to 5.5) that cause a change in the charging characteristics of the capacitor 13, the current supplied to the output line 12 of the current source subcircuit 11, and the state of the charging voltage comparator subcircuit 15. It is executed according to V), and the capacitor 13 repeats charging and discharging periodically according to the curve 25 described in FIG. By supplying this periodic waveform to the subcircuit 15, which is the charging voltage comparison circuit, the beep detection subcircuit 18 is operated in accordance with the curve 26 described in FIG. 2, and the beep detection subcircuit 18 is interleaved. Determine a window 27 that acts to determine whether a locator is requested. This window preferably belongs to 60 to 200 milliseconds. It is generally desirable to keep the sampling long so as to minimize the number of instruments that can be retrieved within a given time period.

In this respect it can be seen that the circuit 1 operates without the need of an external current source. Of course, the capacitor 13 operates as a sufficient current source to sufficiently achieve the desired beep detection. As a result, the circuit component exhibiting the function described above is preferably a micro-class power element in order to check whether the capacitor 13 can provide sufficient current to operate the circuit 1.

If the required beep is not detected, the circuit 1 continues its search function; Among these searchers, an allowable low current is supplied from the connected telephone line 2. When the necessary beep is detected, the beep detecting subcircuit 18 causes the circuit element to be activated to perform the desired interrogation, as described in more detail below. In this case, two processes are performed as a measure to put the accessed telephone line 2 in the response state. First, the instrument is interleaved by connecting the instrument to the starting interrogation unit to access it in an appropriate way through the telephone system. Secondly, once placed in response, telephone company regulations do not further limit the current that can be drawn from the telephone line (2) up to the nominal on-hook value that allows much more current to be drawn from the access telephone line. . This increased supply of current is extracted from (29), which is sufficient to feed the monitoring unit used to retrieve the instrument. After the interrogation is completed, the withdrawal of this increased current is stopped and returned to the idle state for new and periodic interrogation of the circuit 1. At this point, the monitoring device is also reduced to an idle state to keep the customer's telephone line function at an acceptable minimum.

3-5 show the circuit structure described in detail in FIG. 1 and show a state in which an application in which the amount of current drawn in the termination state of the telephone line is limited to a value of 100 microamps is combined.

Accordingly, FIG. 3 shows the telephone line 2 again, and as described above, the telephone line 2 is connected in series with the bridge circuit 7 to generate a current at the terminal 8. The current generated at the pair of load resistors 5 and 6 terminals 8 across is applied to the current source subcircuit 11 as described above. The current source subcircuit 11 comprises a light emitting diode 30, which serves as a useful means for generating a controlled constant reference current useful for charging the capacitor 13 as described above. The voltage across the capacitor 13 causes the charge current comparator subcircuit 5 and the monitor to generate a displacement current at the terminal 14. It is also applied to the charging voltage comparator subcircuit 5 to monitor the voltage displacement generated at the terminal 14 shown in FIG. In response to this, the subcircuit 15, which is a charging voltage comparison circuit, generates an output (shown in FIG. 26) that can periodically act on the switch 17 indicated by the switching transistor. The activation of the switch 17 serves to activate the beep detection circuit 18 as shown in FIG. As described above, the input of the circuit 1 is capacitively coupled to the input 20 of the beep detection circuit 18. The input 20 is provided with a 60 Hz filter 31 for removing noise and an automatic gain controller 32 for adjusting level fluctuations. The output of the automatic gain controller 32 is connected to each of the pair of two-stage sound filters 33, 34, which are configured to selectively detect sound indicative of interrogation. The outputs of the acoustic filters 33 and 34 are each connected to a pair of amplitude comparison circuits 35 and 36, which divide the outputs of the beep filters 33 and 34 into voltage dividers as shown in FIG. The reference voltage 37 generated by the network means 38 is compared. Note that all of the above circuits operate by the current supplied by the capacitor 13, and no external power supply is used at all. For this reason, it is desirable to use micro power circuit elements.

Referring to FIG. 5, the outputs of the amplitude comparison circuits 35 and 36 are connected to switching transistors 40 and 41, which perform the function of an AND circuit. Thus, when two appropriate beeps are supplied to the beep detection subcircuit 18, the signal generates an output 21 which acts to turn on a transistor that activates the circuit 45 for monitoring the instrument in question. A suitable portion of such a supervisory circuit 45 is shown in FIG. For this reason, the hook relay current circuit 46 is started, and sufficient current is drawn from the telephone line 2 so that the telephone line can receive the response state surely. The appropriate voltage is generated by the voltage reference circuit means 47 to start the operation of the monitoring circuit 45. This is to start the interrogation and then perform according to conventionally available, or other known techniques.

In the case of activating the beeper response circuit 1, care should be taken to ensure that the outgoing tones for the selected interrogation are reliably detected by the circuit 1 despite its periodic operation. Thus, it is desirable that the selected beep be present in the circuit 1 over at least the same period as at least one cycle of full charge / discharge of the capacitor 13 (up to 4 seconds).

Even when the monitoring circuit 45 is activated, care must be taken to maintain the operation of the monitoring circuit 45 for a sufficient period of time to perform its function. Since this period usually exceeds the period in which the interrogation beep is imposed on the beep response circuit 1, the transistor 48 is connected in series to the transistor 40 in order to remain in the activated state through the interrogation process. In parallel across the. The sustain transistor 48 receives an input from the multivibration circuit 49 that operates in response to the activation of the monitoring circuit 45. The second multivibrator circuit 50 is provided to enable system service when there is no detected interrogation order.

The circuit structure is intended for use in applications where the telephone company has limited the current drawn from the telephone line feeding the system to the termination state to a value of about 100 microamps. However, sometimes the rules of a sales telephone company limit the current drawn from the telephone line to about 10 microamps. In this case, the circuit regulations need to be careful to achieve the desired operation.

6-8 illustrate a circuit configuration which can operate according to the present invention even when the telephone company's rules limit the current drawn in the telephone company's termination state to a value of 10 microamps or less. Similarly, the circuit configuration of this kind can be operated by increasing the efficiency when an increase in current is available. Therefore, the following circuit configuration according to the present invention is preferable.

Like the circuit 1 described with reference to FIGS. 3-5, the current source subcircuit 11 again serves to limit the current drawn from the terminal 8. However, in the circuit 1 'of FIGS. 6-8, this current is limited to 9.6 microamps. Charging of the capacitor 13 causes the changing voltage to be generated at the terminal 14 according to the characteristic curve shown in FIG.

However, in the specific example of the present invention, this voltage change is a field effect transistor instead of the bipolar transistor and the zener diode of the charge voltage comparator subcircuit 15 so that the auxiliary circuit 15 'can be operated at a lower current level. The generated charging voltage comparator subcircuit 15 'is monitored. As a result of the more possible lower current levels, there is insufficient current to maintain this beep detection circuit as described above. Therefore, only one beep sound is used, and the beep detection circuit 18 'operates to detect the selected single beep sound only when the telephone line 2 indicates the termination state. This is detected by the hook state detection circuit 60 (see FIG. 6).

The beeper detection subcircuit 18 'is a single channel type, single beeper filter 61 and has a square wave circuit 62 instead of the automatic gain control circuit. The square wave circuit 62 generates a constant signal amplitude over the entire range of the specific input signal level and the feed voltage. The output integrator 63 detects the signal level and the duration at the selected frequency. The output of the integrator 63 controls the MOSFET switching switch 41. If the telephone is terminated, the hook state detection subcircuit 60 activates the MOSFET switching transistor 40 and moves the transistor 42 next as described above (set to " ON "). Start the monitoring circuit.

Therefore, it can be seen that serves to achieve each of the above-described purposes. It can also be seen that the foregoing description can be modified without departing from the spirit and scope of the invention. For example, as will be apparent from the foregoing, various circuit elements may be used to provide the functions of the current source subcircuit 11, the charge voltage comparator subcircuit 15, and the beep detection subcircuit 18. Furthermore, the switch 17 can take various forms, if desired. It is also understood that the timing of the circuit elements described above can be changed as needed. Finally, the ringer response circuit 1 of the present invention can be understood according to the telephone company rules. Finally, it is also understood that any beep combination may be used because it activates the beeper response circuit 1 of the present invention in accordance with telephone company rules and starts other unrelated circuits that may be combined with more accessible telephone lines. Could be.

For example, it can also be understood that the beeper selected to activate the beeper response circuit 1 should be selected so as not to match the beeper of what is used in conjunction with the telephone company's pushbutton dial system.

Similarly, the use of tones consistent with the tones used in combination with modulators, telephone answering devices and other peripherals should be avoided. Several telephone companies have been found to be suitable for transmission over telephone lines without interfering with the operation of telephone equipment.

These tones are chosen individually by the telephone company. In the case of using a single beep tone, it is preferable to select one desired beep tone from these lists. In the case of using a plurality of sounds, various pairs of sounds may be selected and combined as necessary. Pairs of additional tones and tones may be assigned according to the telephone company and may be substituted for these values. Such tones are freely selectable as long as they do not interfere with other telephones or peripherals associated with the system, or as long as they are activated. Therefore, arrangements, materials, and details of components described herein and illustrated by way of example in order to explain the characteristics of the invention are intended to be within the scope of the principles and claims of the invention as expressed in the following claims. It will be understood that one of ordinary skill can make changes.

Claims (20)

A start-up circuit used in combination with a system for responding to a start signal and interrogating a remote instrument on a telephone line, said starting circuit being adapted to receive an operating current and a start signal from said telephone line and to communicate with said telephone line. Input means for; Signal detection means (18) for detecting the presence or absence of a start signal on the telephone line and for starting the interrogation system in response to the detection; Means for charging a current received from the telephone line; Means for functionally connecting said input means and said charging means and for limiting said received current when not less than the current required to operate said signal detection means (18); Charge detecting means (15) for detecting a selected current charge amount, generating a trigger signal according to said detection, and coupled with said charging means; And a switching means (17) functionally connected to said charging means and said signal detecting means for operating said signal detecting means (18) in response to said trigger signal. The start circuit according to claim 1, wherein said trigger signal is a periodic signal. 3. The starting circuit according to claim 2, wherein said periodic signal is continued until said starting signal is received. 3. The starting circuit according to claim 2, wherein said charging element is a capacitor. The starting circuit according to claim 4, wherein said charge detecting means is a voltage level detecting circuit. 5. A starting circuit as claimed in claim 4, wherein said current limiting means is a limited current source. 7. The starting circuit according to claim 6, wherein said predominant signal is a sawtooth wave. 8. The starting circuit according to claim 7, wherein the trigger signal is a pulse train. 9. The starting circuit of claim 8, wherein the pulse has a width no less than 60 milliseconds and no greater than 200 milliseconds. The starting circuit of claim 1, wherein the current is limited to no greater than 9.6 microamps. The start circuit according to claim 1, wherein the start signal is a pair of acoustic sounds. 12. The starting circuit according to claim 11, wherein said detecting means is an acoustic detection circuit. 2. The activation circuit of claim 1, wherein the interrogation system further has means for monitoring the remote instrument in accordance with activation of the interrogation. 14. The starting circuit of claim 13 wherein the monitoring means requires a current greater than 9.6 microamps to operate. 2. The telephone line of claim 1, wherein the telephone line is assumed to be on-hook when a current maintained below a defined threshold is drawn from the telephone line, and a current is exceeded from the telephone line above the defined threshold. Start circuit to prevent drawing out. 16. The starting circuit of claim 15 wherein the threshold defined is 100 microamps. 17. The starting circuit of claim 16 wherein the threshold defined is 9.6 microamps. 16. The starting circuit according to claim 15, wherein the telephone line is maintained in an on hook until the signal detecting means detects the starting signal on the telephone line. 19. The apparatus according to claim 18, wherein when the current is drawn out above the threshold defined from the telephone line, the telephone line is assumed to be off hook, and the signal detecting means detects the start signal. A starting circuit for making the telephone line an off hook. 20. The starting circuit according to claim 19, wherein after the interrogation is completed, the telephone line is put on a hook.

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