CA1228184A - Centerpoint automatic meter reading system - Google Patents
Centerpoint automatic meter reading systemInfo
- Publication number
- CA1228184A CA1228184A CA000465718A CA465718A CA1228184A CA 1228184 A CA1228184 A CA 1228184A CA 000465718 A CA000465718 A CA 000465718A CA 465718 A CA465718 A CA 465718A CA 1228184 A CA1228184 A CA 1228184A
- Authority
- CA
- Canada
- Prior art keywords
- alternating current
- representations
- usage information
- telephone
- utility
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
- H04M11/002—Telephonic communication systems specially adapted for combination with other electrical systems with telemetering systems
Abstract
ABSTRACT OF THE DISCLOSURE
The method and apparatus of the present invention is a utility meter reading system for sending utility usage information over a plurality of telephone lines comprising a plurality of in-terface means, at least one interface means coupled to each of the telephone lines and each interface means coupled to at least one utility usage monitor for receiving usage information therefrom and for sending alternating current representations of the usage information over its discrete telephone lines responsive to re-ceiving at least one distinct alternating current interrogation signal over each of the plurality of telephone lines; a means for receiving the plurality of alternating current representations into a plurality of digital representation, each digital repres-entation being a digital representation of usage information from a single utility usage monitor; and, a means for communicating the plurality of digital representations to an external digital inter-facing device.
The method and apparatus of the present invention is a utility meter reading system for sending utility usage information over a plurality of telephone lines comprising a plurality of in-terface means, at least one interface means coupled to each of the telephone lines and each interface means coupled to at least one utility usage monitor for receiving usage information therefrom and for sending alternating current representations of the usage information over its discrete telephone lines responsive to re-ceiving at least one distinct alternating current interrogation signal over each of the plurality of telephone lines; a means for receiving the plurality of alternating current representations into a plurality of digital representation, each digital repres-entation being a digital representation of usage information from a single utility usage monitor; and, a means for communicating the plurality of digital representations to an external digital inter-facing device.
Description
CENTER POINT AUTOMATIC METER READING SYSTEM
BACKGROUND OF THE INVENTION
The present invention is a method and apparatus for receiving utility usage information over a plurality of telephone lines and more particularly a method and apparatus for receiving utility usage information in the form of alternating current representations from a plurality of interface devices, each interface device being coupled to both a distinct telephone line and to at least one utility monitoring device.
There have been other systems for receiving data from telephone lines such as the one described in US. Patent Reissue No. 26, 331 to Dupont et at. Systems of the Dupont type use the telephone company's leakage testing system to call up individual meter installations. Once a meter installation is called up, it sends the meter information over the telephone line to a central telephone office, however, such systems have several disadvantages which make their systems undesirable for its intended use.
First, such systems require the use of a telephone company's leakage testing system to be operable and such lockjaw testing system can change, requiring an additional large invest-mint in new equipment configured to the new leakage testing system.
As well, not all telephone companies have the same type of leakage testing equipment, so that numerous configurations of the meter reading system must be devised to fit the numerous types of leakage testing equipment.
Second, such systems require a power supply, powered either from the power available at the meter I
1 installation site or from battery power for each of its
BACKGROUND OF THE INVENTION
The present invention is a method and apparatus for receiving utility usage information over a plurality of telephone lines and more particularly a method and apparatus for receiving utility usage information in the form of alternating current representations from a plurality of interface devices, each interface device being coupled to both a distinct telephone line and to at least one utility monitoring device.
There have been other systems for receiving data from telephone lines such as the one described in US. Patent Reissue No. 26, 331 to Dupont et at. Systems of the Dupont type use the telephone company's leakage testing system to call up individual meter installations. Once a meter installation is called up, it sends the meter information over the telephone line to a central telephone office, however, such systems have several disadvantages which make their systems undesirable for its intended use.
First, such systems require the use of a telephone company's leakage testing system to be operable and such lockjaw testing system can change, requiring an additional large invest-mint in new equipment configured to the new leakage testing system.
As well, not all telephone companies have the same type of leakage testing equipment, so that numerous configurations of the meter reading system must be devised to fit the numerous types of leakage testing equipment.
Second, such systems require a power supply, powered either from the power available at the meter I
1 installation site or from battery power for each of its
2 Peter installations. This requirement of a power supply
3 makes such systems costly, difficult to service, and
4 makes the systems prone to failures due to common power outages at the installation site.
6 Third, the Dupont invention requires synchronous 7 data output on the telephone line. The synchronous 8 output requires that the meter installations send 9 additional sync data over the telephone line. In the event that either the sync data or synchronous meter data 11 is momentarily interrupted by even a short noise pulse, 12 which is quite common on telephone lines, the melee data 13 will be lost.
14 Another system which has been used to send data over a telephone line is found in US. Patent No.
16 3,922,490 to Putts. The Putts invention is a direct 17 current system where several resistances are switched 18 across tip and ring of the telephone line. The current 19 drawn by the several different combinations of resistances connected to the telephone line are sensed at 21 a central telephone office and any of several conditions 22 are thus communicated. Typically, in the Putts 23 invention, the least significant digit pointer of a 24 utility meter makes or breaks a switch depending on which half of its rotation the pointer is presently located.
26 The making or breaking of the switch causes the 27 resistance across the telephone line to change. This 28 change is sensed at the central office and the cumulative 29 count of changes in transition are totaled and the Inter reading determined therefrom.
31 Of course, the Putts invention, being a I
32 system, does not relate at all to the applicant's 33 invention which is a method and apparatus for receiving , ~L228~
1 data sent in the Norm of alternating current signals over 2 a plurality of telephone lines.
3 US. Patent No. 4,180,709 to Cosgrove et a] also 4 describes a system for enabling the monitoring of a plurality of resistances placed across the DO Tulane 6 line. us with US. Patent Mow 3,922,490, this invention 7 relates only to monitoring data conducted by DO current 8 changes and does not relate at all to the applicant's 9 invention which monitors ARC. signals from the telephone Jo line.
11 zone of the art described has been able to 12 continuously monitor each of a plurality of telephone 13 lines with a low impedance to the ARC. data signals sent 14 and received; none of the art described has been able to receive data from interface devices which are powered 16 from the telephone line; none of the art descried has 17 been able to receive ARC. data which is asynchronous;
18 and, none of the art described has sent utility usage 19 information using dual-tone signals.
2 1 r .
22 SUMMARY Of THE INVENTION
The method and apparatus of the present invention 26 is a utility meter reading system for sending utility 27 usage information over a plurality of telephone lines 28 , comprising a plurality of interface means, at least one 29 interface means coupled to each of the telephone lines and each interface means coupled to at least one utility 31 usage monitor for receiving usage information therefrom 32 and for sending alternating current representations of 33 the usage information over its discrete telephone lines I
1 responsive to receiving at least. one distinct alternating 2 current interrogation signal over each of the plurality 3 of telephone lines; a means for resolving the plurality 4 of alternating current representations into a puerility of digital representation, each 3igital representation 6 being a digital representation of usage infuriation from 7 a single utility usage monitor; and., a means for 8 communicating the plurality of digital representations to 9 an external digital interfacing device.
The interfacing-means may comprise a meter 11 interface device which includes a means for powering the 12 meter interface device from its telephone line, the meter 13 interface device drawing an amount of OWE telephone 14 line current which sustains the telephone line in the OWNER condition during the sending of the alternating 16 current representations. This means for powering the 17 meter interface device may also include means for 18 disabling the meter interface when its telephone inn is 19 in the OFF-HOOK condition. The interrogation sign].
which triggers a particular meter interface device 21 typically comprises a burst of a single audio tone having 22 a frequency of between 300 and 3200 Elertz.
23 The meter interface device may send the 24 alternating current representations as a series of pulses of a pulse width modulated single audio tone, the pulses 26 having at least two different pulse periods. The means 27 for converting the alternating current representations 28 into digital representations may comprise a means for 29 deriving a series of direct current, positive voltage pulses which are proportional in pulse period duration to 31 the pulse period duration of the series of pulses of the 32 single audio tone; and, a means for deriving a series of 33 zero voltage transitions which are proportional in ~22~ 34 duration to the duration of the transition periods between the pulse periods of the series of pulses of the single audio tone.
These proportional positive voltage pulses and zero voltage trays-itchiness may then be decoded in a processor circuit. The result of the decoding is a series of digital signals which represent the usage information from the meter interface devices. The usage information typically comprises a current utility usage figure, meter identification figure and at least one sentinel figure.
Instead ova pulse width modulated single audio tone, the alternating current representations may be in the form of a series of dual-tone signals which represent a utility usage figure and a meter identification figure, there being at least twelve distinct dual-tone signals, each distinct dual-tone signal representing -the following: a digit value between the including 0 to 9, a first framing sentinel and a second framing sentinel.
Thus, in accordance with a broad aspect of the invent lion, there is provided a utility meter reading system for sending utility usage information over a plurality of telephone lines to a telephone central office comprising:
a plurality of interface means, connected to serve a plurality of utility meter locations, at least one interface means coupled to each of the telephone lines and each interface means coupled to at least one utility usage monitor for receiving usage information therefrom and for sending alternating current repro-sensations of the usage information over its discrete telephone line to a telephone central office responsive to receiving at least one distinct alternating current interrogation signal from , Allah its discrete telephone line;
means establishing a continuous ON-HOOK direct current connection between said central office and said plurality of interface means via said telephone lines;
a plurality of multiplexer means at said central office continuously connected to a preselected group of said telephone lines for multiplexing signals communicated between said preset-acted group of telephone lines and said central office;
means at said telephone central office for sending at least one distinct alternating current interrogation signal via said multiplexer means to a plurality of said interface means over each of the plurality of telephone lines;
computer means for selecting each of a plurality of said multiplexer means;
said computer means selecting one of a plurality of telephone lines for receipt of said interrogation signal;
means at said central office for passing ON-HOOK direct current between said central office and said telephone lines whereby said system establishes continuous direct current and at-: 20 ternating current coupling to said telephone lines during ON-COOK conditions;
means at said telephone central office for receiving the plurality of alternating current representations of utility usage information from said plurality of interface means;
means at said telephone central office for converting the alternating current representations into a plurality of digital - pa -I
~22~
representations, each digital representation being a digital representation of utility usage information from a single utility usage meter location; and, means for communicating the plurality of digital repro-sensation to a utility usage information utilization device;
whereby said system allows the monitoring of any of a plurality of remote utility meters selectively under the control of a computer of any ON-HOOK telephone line without the necessity of dialing up any line.
In accordance with another broad aspect of the invention, there is provided the method of sending utility usage information over a plurality of telephone lines comprising the steps of:
Dock and ARC. coupling at least one meter interface device to each of the telephone lines, each of the meter interface devices being coupled to at least one utility usage meter for no-ceiling usage information therefrom and for sending alternating current representations of the usage information over its discrete telephone line responsive to receiving at least one distinct alternating current interrogation signal from its discrete telephone ; line;
continuously powering the interface device by ON-HOOK
current on the telephone line;
multiplexing said alternating current representations of usage information and interrogation signals;
sending at least one distinct alternating current inter-rotation signal over each of the plurality of telephone lines;
receiving the plurality of alternating current ~;~. - 5b -Jo ~L22~
representations of the usage information;
converting the alternating current representations into a plurality of digital representations, each digital representation being a digital representation of usage information from a single utility usage monitor; and communicating the plurality of digital representations to an external digital interfacing device;
in which the alternating current representations come prose a series of dual-tones, each dual tone representing at least a single digit value between and including 0 and 9 and a first and second framing sentinel.
IFFY DESCRIPTION OF THE DRAWINGS
This invention may be more clearly understood from the following detailed description and by reference to the drawing in which:
Figure 1 is an electrical block diagram of the utility meter reading system of the present invention;
Figure 2 is an electrical block diagram of there furred embodiment of the meter interface device of the present invention;
Figure 3 is an electrical block diagram of the pro-furred embodiment of the multiplexing system of the - 5c -.,, lZZ8~B4 present invention;
Figure 4 is an electrical block diagram of the pro-furred embodiment of the multiplexer device of the present invent lion; and Figure 5 is an electrical block diagram of an alternate embodiment of the meter interface device of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to Figure 1, the present invention is an apparatus and method for reading utility meters over telephone lines 12 and more particularly with receiving alternating current representations of utility usage information from a plurality of meters 16 via interface devices 16, typically located at a sub-scriber's site. The sending of the alternating current represent-lions from each of the meter interface devices 14 to the telephone company site is responsive to receiving a particular distinct interrogation signal from the telephone central office 20 multiplexer system. A detailed description of a suitable meter interface device may be found in United States patent 4,540,849 issued September 10, 1985 to Stewart W. Oliver for a Meter Interface Device for An Automatic Meter Reading System. A detailed desert-potion of the multiplexer system 20 may be found in co-pending Canadian application Serial No. 465,841 filed October 18, 1984 for a Multiplexing System for An Automatic Meter Reading System.
The alternating current representations of meter 16 readings from the meter interface devices 14 are received by at least one multiplexer device 22 in the it ~2;2E3~L~34 1 multiplexer system 20 which converts the alternating 2 current representations into digital representations and 3 typically sends the digital representations to a computer 4 24.
The multiplexer system 20 is typically located in 6 the central office of a telephone company. The telephone 7 company may access the usage information in the computer 8 by local terminal 23 and printer 25. The usage 9 information in the computer I may also be sent to other in locations via high speed or owe speed data lines 26 and 11 28. The multiplexer devices 22 are typically connected 12 to the plurality of telephone lines 12 at a point past 13 the cut-off relays 27 so that there is a continuous 14 coupling to the telephone lines 12 even when the telephone lines 12 are in the OFF-HCOX condition, 16 although any point of access to either one or both sides 17 of the line is acceptable.
21 Referring to Figure 2, the preferred embodiment 22 of the meter interface device 14 is shown. The meter 23 interface device 14 typically is powered by the telephone 24 line 12 through power supply 50. This power supply sun may be configured to cause the meter interface device I
26 to become inoperative during the OFF-HOOK conditions on 27 the telephone line 12. Also, the device can only conduct 28 ; ON-HOOK battery current in a unpiler fashion along 29 precise line leakage measurements to still be made using a reverse battery, (i.e. ring conductor positive with 31 respect to tip conductor.) An interrogation signal 32 detector circuit 60 is used to respond to the reception 33 of a particular distinct interrogation signal sent over I
the telephone line 12. When -the particular distinct interrogation signal is received by the interrogation signal detector circuit 60, a signal is sent to the control logic circuit 70 which, in turn, powers the utility monitoring device 16 through transistor Q4 and starts the clock circuit 80 outputting clock signals to the utility monitoring device 16.
The output of the utility monitoring device 16 will typically pulse width modulate a single audio carrier from carrier oscillator circuit 90. The frequency of the carrier produced in the carrier oscillator circuit 100 found to be most advantageous is 2000 Hertz. This 2000 Hertz frequency is in the mid-range of the band pass of most telephone company equipment and yet of a frequency sufficiently high to allow a reasonably fast data rate.
The pulse width modulated single audio tone is amplified and coupled to the telephone line 12 by output stage 100 and rise time limiter and output attenuator 110.
The preferred embodiment of the meter interface device 14 is configured to be interface able with a water meter of the type described in United States Patent No. 4,085,287 to Pullman et at. Suffice it to say that the Pullman water meter monitors water usage by the position of four rotary switches. The position of each of these switches is sent to an output line as pulse width modulated digital signals tree Figure 8 of Pullman). The digital signals represent digit values of a usage figure, meter identifica-lion figure and sentinel figures. The meter interface device 14 sends these figures as alternating current representations. How-ever, it must be noted that the preferred embodiment of the meter interface device 14 can be configured to , .
~L~21~84 1 interface to virtual at]. utility monitoring devices.
2 Now referring to Figure 3, the multiplexer system 3 20 is seen. The multiplexer system Topeka has a computer line buffer 35 which can interface the multiplexer system 20 to a computer I or other parallel 6 digital interfacing devices. The computer line buffer 35 7 typically interfaces a 16 kit plus a strobe out-going line 32 from the computer 24 and an 8 bit incoming line 9 34 to the computer 24. The 16 bit outgoing inn 32 carries control signals which, among other tasks, tell 11 the multiplexer devices 22 to interrogate a particular 12 subscriber's telephone line 12.
13 The 16 bits are broken down first into 8 MU
14 select bits which allow the computer 24 to access 256 different multiplexer devices 22. Each multiplexer 16 device 22 can typically receive data from 50 double-ended 17 telephone lines I or 100 sinc~le-ended Tiffany lines 18 12. on additional 7 bits of the 3.6 bit signals from the 19 computer 24 are typically used for individual telephone I line select codes. The remaining bit of the 16 plus the 21 strobe are used for handshaking between the digital 22 interface device and the mu].tip].exer device.
23 The 100 telephone lines connected to each 24 multiplexer device 22 can, therefore, be individually accessed and controlled by the computer 24 by selecting 26 the proper telephone line select code. Thus, it can be 27 seen that computer 24 can access up to 25,600 Tiffany 28 ions in the preferred embodiment of the multiplexer 29 system 20. As well, each telephone line 12 may have a plurality of meter interface devices 14 coupled to it, 31 and, each meter interface device 14 can have a plurality 32 of utility usage monitors 16 coupled to it. Since a 33 plurality of distinct interrogation signals can be sent I I
~2~8~
over every coupled telephone line 12 by the mu]tiplexincJ
2 system 20, well over a 100,000 individual newer readings 3 can be read by the preferred embodiment of the 4 multiplexer system 20.
Since the preferred embodiment of the multiplexer 6 system 20 can be cowled to a minimum of 100 telephone 7 lines 12, there are 28 different telephone line select 8 codes left which can be used as control codes to the 9 processor circuit 120 (shown in Figure 4) of the multiplexer device 22. The retaining 1 bit is typically 11 used as a MU reset command which will cause the software 12 in any particular multiplexer device 22 to reinitialize 13 and ready itself for another meter reading attempt.
14 Since the computer 24 is typically ].ocatecl some distance away from the cages 80 which house the 16 multiplexer devices 22, the signals to and from the 17 computer 24 will have to travel over a relatively long 18 distance. To prevent loss of signals and increased noise 19 susceptibility over the long distance, each of the 16 bit out-going and 8 bit incoming lines 32 and 34 are 21 amplified before entering the cable 40 and optically 22 coupled at its intended receiving point The 16 bit 23 signals plus the strobe on the 16 bit out-going line 32 24 are amplified by line driver stage 37 and optically coupled to optical coupler stage 42 in the master line 26 driver receiver 52. The 8 bit lines from the slave line 27 driver/receiver 62 are line amplified by inn driver 28 stage 44 in the master line driver/receiver 52 and 29 optically coupled in optical coupler stage 39 in the computer line buffer 35.
31 Typically, each cage 80 can house twenty 32 multiplexer devices 22 along with a power supply 64 and 33 the slave line driver/receiver 62. However, since each Lay 1 cage 80 shares a swung I/O line 54 from the master line 2 driver/receiver 52, in order to drive the twenty 3 multiplexer devices 22 in each cage I the signal levels 4 must be boosted. The boosting of the signal levels is done in each of the slave line driver/receivers 62.
6 Jo Typically, each cage 80 has a wire-wrap section 7 which allows a standardized multiplexer device 22 to 8 be installed in each position in the cage I and 9 instantly acquire the necessary distinct hard wiring which 1,0 tells the multiplexer device 22 which one it is ion the ]. overall picture of the plurality of multiplexer devices 12 22 and tells the multiplexer device 22 whether it is in 13 the single or double ended configuration. '"
14 Referring to Figure 4, a typical multiplexer device 22 is seen. The telephone lines 12 are connected 16 to input circuits 102 which protect the multiplexer 17 device 22 from high voltage conditions on the telephone 18 line 12, provide a low impedance path to audio signals to 19 and from the multiplexer device 22 and allow a spa]].
direct current leakage to enter the multiplexer device 22 21 from the telephone line 12 to Allah the sensing of an 22 OFF-HOOK condition on the telephone line 12.
23 Each of the telephone lines 12 are de-multip]exed 24 to a single transmit/receive line ],04, and, transmit/receive line 104 is also multiplexed to the 26 proper telephone line by the multiplexer stage 98 under 27 the control of the processor circuit 120 which, in turn, 28 i is commanded by the computer 24 or Figure 2. Skinless 29 received or sent over the telephone lines I are switched by transmit and receive switch 106 under the control of 31 the processor circuit 120.
32 Since a small amount of direct current is leaked 33 to the multiplexer device 22, OFF-~OOK detector circuit ^
1 10P, can detect an OFF condition by sensing a 2 dramatic drop in voltage from the voltage appearing on 3 the telephone line in the ON-HOOK condition.
4 The received alternating current representations from the meter interface devices 14 are processed in 6 receiver circuit 150. As in the preferred embodiment of 7 the meter interface device 14, the alternating current 8 representations are in the form of a series of pulses of 9 a pulse width modulated carrier. The receiver 150 filters the representation and converts them into I positive, direct current digital pulses which have pulse 12 periods proportional to the pulse periods of the pulses 13 of the pulse width modulated carrier. These digital 14 pulses are sent to the processor circuit 120 for further decoding and extensive software filtering. Once decoded, 16 the usage figure and meter identification figure are sent 17 to the computer 24 as a series of binary digital words.
18 If the alternating current representations are in the 19 form of dual-tone signals, as they are in the alternate embodiment of the meter interface devices 14, then the 21 receiver 150 decodes the usage information into a series 22 of digital words which are sent to the computer 24 via 23 the processor 12n.
24 The multiplexer device 22 typically sends the interrogation signal as a tone burst of a single 26 frequency between 300 and 3200 Hertz. In the preferred 27 embodiment, the processor 12n creates the interrogation 28 signals, and the frequencies of 500 Hertz, 810 Hertz and 29 1270 Hertz have been found to operate satisfactorily with telephone company equipment. Each of these distinct 31 frequencies can activate a separate meter interface 32 device on the same line. Each mater interface device can 33 sequentially send usage data for a multiple of usage ~12-monitoring devices enabling each phone line to~ommunicate 2 usage data for nay separate monitoring devices. The 3 current embodiment has four meter interface crevices or a 4 capacity of twelve per line. The tone burst, generated in the processor circuit 120, is controlled in amplitude 6 by the processor 120 in DOW converter 112. The analog 7 tone burst signal is then amplified and switched to the 8 appropriate telephone line 12 via transmit receive switch 9 106 and multiplexer stage 98. -The utility usage information from the meter 11 interface devices 22 typically coTrprises a current 12 utility usage figure and a meter identification figure.
13 These are sent to the computer 24 via the slave line 14 driver/receiver 62, master line driver/receiver 52 and computer line buffer 35.
I
19 Referring to Figure 5, the alternate embodiment of the meter interface device 14 is seen. The 21 configuration in Figure 5 is shown interfaced to the 22 Pullman type water meter of US. Patent 4,085,2B7, 23 however, as previously noted, virtually any utility 24 monitoring device may be interfaced to the meter interface device 14. The alternate embodiment of the 26 meter interface device 14 differs from the preferred 27 embodiment of Figure 2 in that the meter switches in the 28 Pullman water meter are scanned by the meter dial scan 29 logic circuit 200 so that the DTMF transmitter 230 will send a distinct dual-tone signal for each digit of the 31 Pullman water meter indicated by the switch positions on 32 the row 210 and co] urn 220 lines. These clual-tone 33 signals are then sent over the telephone line 12.
I
1 It can be seen from the foregoing that the meter 2 reading system 10 of the present invention has the 3 advantages of flexibility in the sending and receiving of 4 the utility usage information. The processor circuit 120 can decode numerous types of digital signals sent to it 6 by the receiver stage 150 of Figure 4. us well, the 7 meter interface devices 14 can be interfaced to numerous 8 types of utility monitoring devices and send decidable 9 alternating current representations of the utility usage information. us described, the present invention can 11 send, receive and decode asynchronous data over the 12 telephone line.
13 The above described embodiments of the present lo invention are merely descriptive of its principles and are not to be considered limiting. The scope of the 16 present invention instead shall be determined from the 17 scope of the following claims, including their 18 equivalents.
6 Third, the Dupont invention requires synchronous 7 data output on the telephone line. The synchronous 8 output requires that the meter installations send 9 additional sync data over the telephone line. In the event that either the sync data or synchronous meter data 11 is momentarily interrupted by even a short noise pulse, 12 which is quite common on telephone lines, the melee data 13 will be lost.
14 Another system which has been used to send data over a telephone line is found in US. Patent No.
16 3,922,490 to Putts. The Putts invention is a direct 17 current system where several resistances are switched 18 across tip and ring of the telephone line. The current 19 drawn by the several different combinations of resistances connected to the telephone line are sensed at 21 a central telephone office and any of several conditions 22 are thus communicated. Typically, in the Putts 23 invention, the least significant digit pointer of a 24 utility meter makes or breaks a switch depending on which half of its rotation the pointer is presently located.
26 The making or breaking of the switch causes the 27 resistance across the telephone line to change. This 28 change is sensed at the central office and the cumulative 29 count of changes in transition are totaled and the Inter reading determined therefrom.
31 Of course, the Putts invention, being a I
32 system, does not relate at all to the applicant's 33 invention which is a method and apparatus for receiving , ~L228~
1 data sent in the Norm of alternating current signals over 2 a plurality of telephone lines.
3 US. Patent No. 4,180,709 to Cosgrove et a] also 4 describes a system for enabling the monitoring of a plurality of resistances placed across the DO Tulane 6 line. us with US. Patent Mow 3,922,490, this invention 7 relates only to monitoring data conducted by DO current 8 changes and does not relate at all to the applicant's 9 invention which monitors ARC. signals from the telephone Jo line.
11 zone of the art described has been able to 12 continuously monitor each of a plurality of telephone 13 lines with a low impedance to the ARC. data signals sent 14 and received; none of the art described has been able to receive data from interface devices which are powered 16 from the telephone line; none of the art descried has 17 been able to receive ARC. data which is asynchronous;
18 and, none of the art described has sent utility usage 19 information using dual-tone signals.
2 1 r .
22 SUMMARY Of THE INVENTION
The method and apparatus of the present invention 26 is a utility meter reading system for sending utility 27 usage information over a plurality of telephone lines 28 , comprising a plurality of interface means, at least one 29 interface means coupled to each of the telephone lines and each interface means coupled to at least one utility 31 usage monitor for receiving usage information therefrom 32 and for sending alternating current representations of 33 the usage information over its discrete telephone lines I
1 responsive to receiving at least. one distinct alternating 2 current interrogation signal over each of the plurality 3 of telephone lines; a means for resolving the plurality 4 of alternating current representations into a puerility of digital representation, each 3igital representation 6 being a digital representation of usage infuriation from 7 a single utility usage monitor; and., a means for 8 communicating the plurality of digital representations to 9 an external digital interfacing device.
The interfacing-means may comprise a meter 11 interface device which includes a means for powering the 12 meter interface device from its telephone line, the meter 13 interface device drawing an amount of OWE telephone 14 line current which sustains the telephone line in the OWNER condition during the sending of the alternating 16 current representations. This means for powering the 17 meter interface device may also include means for 18 disabling the meter interface when its telephone inn is 19 in the OFF-HOOK condition. The interrogation sign].
which triggers a particular meter interface device 21 typically comprises a burst of a single audio tone having 22 a frequency of between 300 and 3200 Elertz.
23 The meter interface device may send the 24 alternating current representations as a series of pulses of a pulse width modulated single audio tone, the pulses 26 having at least two different pulse periods. The means 27 for converting the alternating current representations 28 into digital representations may comprise a means for 29 deriving a series of direct current, positive voltage pulses which are proportional in pulse period duration to 31 the pulse period duration of the series of pulses of the 32 single audio tone; and, a means for deriving a series of 33 zero voltage transitions which are proportional in ~22~ 34 duration to the duration of the transition periods between the pulse periods of the series of pulses of the single audio tone.
These proportional positive voltage pulses and zero voltage trays-itchiness may then be decoded in a processor circuit. The result of the decoding is a series of digital signals which represent the usage information from the meter interface devices. The usage information typically comprises a current utility usage figure, meter identification figure and at least one sentinel figure.
Instead ova pulse width modulated single audio tone, the alternating current representations may be in the form of a series of dual-tone signals which represent a utility usage figure and a meter identification figure, there being at least twelve distinct dual-tone signals, each distinct dual-tone signal representing -the following: a digit value between the including 0 to 9, a first framing sentinel and a second framing sentinel.
Thus, in accordance with a broad aspect of the invent lion, there is provided a utility meter reading system for sending utility usage information over a plurality of telephone lines to a telephone central office comprising:
a plurality of interface means, connected to serve a plurality of utility meter locations, at least one interface means coupled to each of the telephone lines and each interface means coupled to at least one utility usage monitor for receiving usage information therefrom and for sending alternating current repro-sensations of the usage information over its discrete telephone line to a telephone central office responsive to receiving at least one distinct alternating current interrogation signal from , Allah its discrete telephone line;
means establishing a continuous ON-HOOK direct current connection between said central office and said plurality of interface means via said telephone lines;
a plurality of multiplexer means at said central office continuously connected to a preselected group of said telephone lines for multiplexing signals communicated between said preset-acted group of telephone lines and said central office;
means at said telephone central office for sending at least one distinct alternating current interrogation signal via said multiplexer means to a plurality of said interface means over each of the plurality of telephone lines;
computer means for selecting each of a plurality of said multiplexer means;
said computer means selecting one of a plurality of telephone lines for receipt of said interrogation signal;
means at said central office for passing ON-HOOK direct current between said central office and said telephone lines whereby said system establishes continuous direct current and at-: 20 ternating current coupling to said telephone lines during ON-COOK conditions;
means at said telephone central office for receiving the plurality of alternating current representations of utility usage information from said plurality of interface means;
means at said telephone central office for converting the alternating current representations into a plurality of digital - pa -I
~22~
representations, each digital representation being a digital representation of utility usage information from a single utility usage meter location; and, means for communicating the plurality of digital repro-sensation to a utility usage information utilization device;
whereby said system allows the monitoring of any of a plurality of remote utility meters selectively under the control of a computer of any ON-HOOK telephone line without the necessity of dialing up any line.
In accordance with another broad aspect of the invention, there is provided the method of sending utility usage information over a plurality of telephone lines comprising the steps of:
Dock and ARC. coupling at least one meter interface device to each of the telephone lines, each of the meter interface devices being coupled to at least one utility usage meter for no-ceiling usage information therefrom and for sending alternating current representations of the usage information over its discrete telephone line responsive to receiving at least one distinct alternating current interrogation signal from its discrete telephone ; line;
continuously powering the interface device by ON-HOOK
current on the telephone line;
multiplexing said alternating current representations of usage information and interrogation signals;
sending at least one distinct alternating current inter-rotation signal over each of the plurality of telephone lines;
receiving the plurality of alternating current ~;~. - 5b -Jo ~L22~
representations of the usage information;
converting the alternating current representations into a plurality of digital representations, each digital representation being a digital representation of usage information from a single utility usage monitor; and communicating the plurality of digital representations to an external digital interfacing device;
in which the alternating current representations come prose a series of dual-tones, each dual tone representing at least a single digit value between and including 0 and 9 and a first and second framing sentinel.
IFFY DESCRIPTION OF THE DRAWINGS
This invention may be more clearly understood from the following detailed description and by reference to the drawing in which:
Figure 1 is an electrical block diagram of the utility meter reading system of the present invention;
Figure 2 is an electrical block diagram of there furred embodiment of the meter interface device of the present invention;
Figure 3 is an electrical block diagram of the pro-furred embodiment of the multiplexing system of the - 5c -.,, lZZ8~B4 present invention;
Figure 4 is an electrical block diagram of the pro-furred embodiment of the multiplexer device of the present invent lion; and Figure 5 is an electrical block diagram of an alternate embodiment of the meter interface device of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to Figure 1, the present invention is an apparatus and method for reading utility meters over telephone lines 12 and more particularly with receiving alternating current representations of utility usage information from a plurality of meters 16 via interface devices 16, typically located at a sub-scriber's site. The sending of the alternating current represent-lions from each of the meter interface devices 14 to the telephone company site is responsive to receiving a particular distinct interrogation signal from the telephone central office 20 multiplexer system. A detailed description of a suitable meter interface device may be found in United States patent 4,540,849 issued September 10, 1985 to Stewart W. Oliver for a Meter Interface Device for An Automatic Meter Reading System. A detailed desert-potion of the multiplexer system 20 may be found in co-pending Canadian application Serial No. 465,841 filed October 18, 1984 for a Multiplexing System for An Automatic Meter Reading System.
The alternating current representations of meter 16 readings from the meter interface devices 14 are received by at least one multiplexer device 22 in the it ~2;2E3~L~34 1 multiplexer system 20 which converts the alternating 2 current representations into digital representations and 3 typically sends the digital representations to a computer 4 24.
The multiplexer system 20 is typically located in 6 the central office of a telephone company. The telephone 7 company may access the usage information in the computer 8 by local terminal 23 and printer 25. The usage 9 information in the computer I may also be sent to other in locations via high speed or owe speed data lines 26 and 11 28. The multiplexer devices 22 are typically connected 12 to the plurality of telephone lines 12 at a point past 13 the cut-off relays 27 so that there is a continuous 14 coupling to the telephone lines 12 even when the telephone lines 12 are in the OFF-HCOX condition, 16 although any point of access to either one or both sides 17 of the line is acceptable.
21 Referring to Figure 2, the preferred embodiment 22 of the meter interface device 14 is shown. The meter 23 interface device 14 typically is powered by the telephone 24 line 12 through power supply 50. This power supply sun may be configured to cause the meter interface device I
26 to become inoperative during the OFF-HOOK conditions on 27 the telephone line 12. Also, the device can only conduct 28 ; ON-HOOK battery current in a unpiler fashion along 29 precise line leakage measurements to still be made using a reverse battery, (i.e. ring conductor positive with 31 respect to tip conductor.) An interrogation signal 32 detector circuit 60 is used to respond to the reception 33 of a particular distinct interrogation signal sent over I
the telephone line 12. When -the particular distinct interrogation signal is received by the interrogation signal detector circuit 60, a signal is sent to the control logic circuit 70 which, in turn, powers the utility monitoring device 16 through transistor Q4 and starts the clock circuit 80 outputting clock signals to the utility monitoring device 16.
The output of the utility monitoring device 16 will typically pulse width modulate a single audio carrier from carrier oscillator circuit 90. The frequency of the carrier produced in the carrier oscillator circuit 100 found to be most advantageous is 2000 Hertz. This 2000 Hertz frequency is in the mid-range of the band pass of most telephone company equipment and yet of a frequency sufficiently high to allow a reasonably fast data rate.
The pulse width modulated single audio tone is amplified and coupled to the telephone line 12 by output stage 100 and rise time limiter and output attenuator 110.
The preferred embodiment of the meter interface device 14 is configured to be interface able with a water meter of the type described in United States Patent No. 4,085,287 to Pullman et at. Suffice it to say that the Pullman water meter monitors water usage by the position of four rotary switches. The position of each of these switches is sent to an output line as pulse width modulated digital signals tree Figure 8 of Pullman). The digital signals represent digit values of a usage figure, meter identifica-lion figure and sentinel figures. The meter interface device 14 sends these figures as alternating current representations. How-ever, it must be noted that the preferred embodiment of the meter interface device 14 can be configured to , .
~L~21~84 1 interface to virtual at]. utility monitoring devices.
2 Now referring to Figure 3, the multiplexer system 3 20 is seen. The multiplexer system Topeka has a computer line buffer 35 which can interface the multiplexer system 20 to a computer I or other parallel 6 digital interfacing devices. The computer line buffer 35 7 typically interfaces a 16 kit plus a strobe out-going line 32 from the computer 24 and an 8 bit incoming line 9 34 to the computer 24. The 16 bit outgoing inn 32 carries control signals which, among other tasks, tell 11 the multiplexer devices 22 to interrogate a particular 12 subscriber's telephone line 12.
13 The 16 bits are broken down first into 8 MU
14 select bits which allow the computer 24 to access 256 different multiplexer devices 22. Each multiplexer 16 device 22 can typically receive data from 50 double-ended 17 telephone lines I or 100 sinc~le-ended Tiffany lines 18 12. on additional 7 bits of the 3.6 bit signals from the 19 computer 24 are typically used for individual telephone I line select codes. The remaining bit of the 16 plus the 21 strobe are used for handshaking between the digital 22 interface device and the mu].tip].exer device.
23 The 100 telephone lines connected to each 24 multiplexer device 22 can, therefore, be individually accessed and controlled by the computer 24 by selecting 26 the proper telephone line select code. Thus, it can be 27 seen that computer 24 can access up to 25,600 Tiffany 28 ions in the preferred embodiment of the multiplexer 29 system 20. As well, each telephone line 12 may have a plurality of meter interface devices 14 coupled to it, 31 and, each meter interface device 14 can have a plurality 32 of utility usage monitors 16 coupled to it. Since a 33 plurality of distinct interrogation signals can be sent I I
~2~8~
over every coupled telephone line 12 by the mu]tiplexincJ
2 system 20, well over a 100,000 individual newer readings 3 can be read by the preferred embodiment of the 4 multiplexer system 20.
Since the preferred embodiment of the multiplexer 6 system 20 can be cowled to a minimum of 100 telephone 7 lines 12, there are 28 different telephone line select 8 codes left which can be used as control codes to the 9 processor circuit 120 (shown in Figure 4) of the multiplexer device 22. The retaining 1 bit is typically 11 used as a MU reset command which will cause the software 12 in any particular multiplexer device 22 to reinitialize 13 and ready itself for another meter reading attempt.
14 Since the computer 24 is typically ].ocatecl some distance away from the cages 80 which house the 16 multiplexer devices 22, the signals to and from the 17 computer 24 will have to travel over a relatively long 18 distance. To prevent loss of signals and increased noise 19 susceptibility over the long distance, each of the 16 bit out-going and 8 bit incoming lines 32 and 34 are 21 amplified before entering the cable 40 and optically 22 coupled at its intended receiving point The 16 bit 23 signals plus the strobe on the 16 bit out-going line 32 24 are amplified by line driver stage 37 and optically coupled to optical coupler stage 42 in the master line 26 driver receiver 52. The 8 bit lines from the slave line 27 driver/receiver 62 are line amplified by inn driver 28 stage 44 in the master line driver/receiver 52 and 29 optically coupled in optical coupler stage 39 in the computer line buffer 35.
31 Typically, each cage 80 can house twenty 32 multiplexer devices 22 along with a power supply 64 and 33 the slave line driver/receiver 62. However, since each Lay 1 cage 80 shares a swung I/O line 54 from the master line 2 driver/receiver 52, in order to drive the twenty 3 multiplexer devices 22 in each cage I the signal levels 4 must be boosted. The boosting of the signal levels is done in each of the slave line driver/receivers 62.
6 Jo Typically, each cage 80 has a wire-wrap section 7 which allows a standardized multiplexer device 22 to 8 be installed in each position in the cage I and 9 instantly acquire the necessary distinct hard wiring which 1,0 tells the multiplexer device 22 which one it is ion the ]. overall picture of the plurality of multiplexer devices 12 22 and tells the multiplexer device 22 whether it is in 13 the single or double ended configuration. '"
14 Referring to Figure 4, a typical multiplexer device 22 is seen. The telephone lines 12 are connected 16 to input circuits 102 which protect the multiplexer 17 device 22 from high voltage conditions on the telephone 18 line 12, provide a low impedance path to audio signals to 19 and from the multiplexer device 22 and allow a spa]].
direct current leakage to enter the multiplexer device 22 21 from the telephone line 12 to Allah the sensing of an 22 OFF-HOOK condition on the telephone line 12.
23 Each of the telephone lines 12 are de-multip]exed 24 to a single transmit/receive line ],04, and, transmit/receive line 104 is also multiplexed to the 26 proper telephone line by the multiplexer stage 98 under 27 the control of the processor circuit 120 which, in turn, 28 i is commanded by the computer 24 or Figure 2. Skinless 29 received or sent over the telephone lines I are switched by transmit and receive switch 106 under the control of 31 the processor circuit 120.
32 Since a small amount of direct current is leaked 33 to the multiplexer device 22, OFF-~OOK detector circuit ^
1 10P, can detect an OFF condition by sensing a 2 dramatic drop in voltage from the voltage appearing on 3 the telephone line in the ON-HOOK condition.
4 The received alternating current representations from the meter interface devices 14 are processed in 6 receiver circuit 150. As in the preferred embodiment of 7 the meter interface device 14, the alternating current 8 representations are in the form of a series of pulses of 9 a pulse width modulated carrier. The receiver 150 filters the representation and converts them into I positive, direct current digital pulses which have pulse 12 periods proportional to the pulse periods of the pulses 13 of the pulse width modulated carrier. These digital 14 pulses are sent to the processor circuit 120 for further decoding and extensive software filtering. Once decoded, 16 the usage figure and meter identification figure are sent 17 to the computer 24 as a series of binary digital words.
18 If the alternating current representations are in the 19 form of dual-tone signals, as they are in the alternate embodiment of the meter interface devices 14, then the 21 receiver 150 decodes the usage information into a series 22 of digital words which are sent to the computer 24 via 23 the processor 12n.
24 The multiplexer device 22 typically sends the interrogation signal as a tone burst of a single 26 frequency between 300 and 3200 Hertz. In the preferred 27 embodiment, the processor 12n creates the interrogation 28 signals, and the frequencies of 500 Hertz, 810 Hertz and 29 1270 Hertz have been found to operate satisfactorily with telephone company equipment. Each of these distinct 31 frequencies can activate a separate meter interface 32 device on the same line. Each mater interface device can 33 sequentially send usage data for a multiple of usage ~12-monitoring devices enabling each phone line to~ommunicate 2 usage data for nay separate monitoring devices. The 3 current embodiment has four meter interface crevices or a 4 capacity of twelve per line. The tone burst, generated in the processor circuit 120, is controlled in amplitude 6 by the processor 120 in DOW converter 112. The analog 7 tone burst signal is then amplified and switched to the 8 appropriate telephone line 12 via transmit receive switch 9 106 and multiplexer stage 98. -The utility usage information from the meter 11 interface devices 22 typically coTrprises a current 12 utility usage figure and a meter identification figure.
13 These are sent to the computer 24 via the slave line 14 driver/receiver 62, master line driver/receiver 52 and computer line buffer 35.
I
19 Referring to Figure 5, the alternate embodiment of the meter interface device 14 is seen. The 21 configuration in Figure 5 is shown interfaced to the 22 Pullman type water meter of US. Patent 4,085,2B7, 23 however, as previously noted, virtually any utility 24 monitoring device may be interfaced to the meter interface device 14. The alternate embodiment of the 26 meter interface device 14 differs from the preferred 27 embodiment of Figure 2 in that the meter switches in the 28 Pullman water meter are scanned by the meter dial scan 29 logic circuit 200 so that the DTMF transmitter 230 will send a distinct dual-tone signal for each digit of the 31 Pullman water meter indicated by the switch positions on 32 the row 210 and co] urn 220 lines. These clual-tone 33 signals are then sent over the telephone line 12.
I
1 It can be seen from the foregoing that the meter 2 reading system 10 of the present invention has the 3 advantages of flexibility in the sending and receiving of 4 the utility usage information. The processor circuit 120 can decode numerous types of digital signals sent to it 6 by the receiver stage 150 of Figure 4. us well, the 7 meter interface devices 14 can be interfaced to numerous 8 types of utility monitoring devices and send decidable 9 alternating current representations of the utility usage information. us described, the present invention can 11 send, receive and decode asynchronous data over the 12 telephone line.
13 The above described embodiments of the present lo invention are merely descriptive of its principles and are not to be considered limiting. The scope of the 16 present invention instead shall be determined from the 17 scope of the following claims, including their 18 equivalents.
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A utility meter reading system for sending utility usage information over a plurality of subscriber voice channel telephone lines to a telephone central office comprising:
a plurality of subscriber channel voice interface means, connected to serve a plurality of utility meter locations, at least one interface means coupled to each of the telephone lines and each interface means coupled to at least one utility usage monitor for receiving usage information therefrom and for sending alter-nating current representations of the usage information over its discrete telephone line to a telephone central office responsive to receiving at least one distinct alternating current interroga-tion signal from its discrete telephone line;
means establishing a continuous ON-HOOK direct current connection between said central office and said plurality of interface means via said telephone lines;
a plurality of multiplexer means at said central office continuously connected to a preselected group of said telephone lines for multiplexing signals communicated between said pre-selected group of telephone lines and said central office;
means at said telephone central office for sending at least one distinct alternating current interrogation signal via said multiplexer means to a plurality of said interface means over each of the plurality of telephone lines;
computer means for selecting each of a plurality of said multiplexer means;
said computer means selecting one of a plurality of telephone lines for receipt of said interrogation signal;
means at said central office for passing ON-HOOK direct current between said central office and said telephone lines whereby said system establishes continuous direct current and alternating current coupling to said telephone lines during ON-HOOK
conditions;
means at said telephone central office for receiving the plurality of alternating current representations of utility usage information from said plurality of interface means;
means at said telephone central office for converting the alternating current representations into a plurality of digital representations, each digital representation being a digital re-presentation of utility usage information from a single utility usage meter location; and, means for communicating the plurality of digital representations to a utility usage information utilization device;
whereby said system allows the monitoring of any of a plurality of remote utility meters selectively under the control of a computer of any ON-HOOK telephone line without the necessity of dialing up any line.
a plurality of subscriber channel voice interface means, connected to serve a plurality of utility meter locations, at least one interface means coupled to each of the telephone lines and each interface means coupled to at least one utility usage monitor for receiving usage information therefrom and for sending alter-nating current representations of the usage information over its discrete telephone line to a telephone central office responsive to receiving at least one distinct alternating current interroga-tion signal from its discrete telephone line;
means establishing a continuous ON-HOOK direct current connection between said central office and said plurality of interface means via said telephone lines;
a plurality of multiplexer means at said central office continuously connected to a preselected group of said telephone lines for multiplexing signals communicated between said pre-selected group of telephone lines and said central office;
means at said telephone central office for sending at least one distinct alternating current interrogation signal via said multiplexer means to a plurality of said interface means over each of the plurality of telephone lines;
computer means for selecting each of a plurality of said multiplexer means;
said computer means selecting one of a plurality of telephone lines for receipt of said interrogation signal;
means at said central office for passing ON-HOOK direct current between said central office and said telephone lines whereby said system establishes continuous direct current and alternating current coupling to said telephone lines during ON-HOOK
conditions;
means at said telephone central office for receiving the plurality of alternating current representations of utility usage information from said plurality of interface means;
means at said telephone central office for converting the alternating current representations into a plurality of digital representations, each digital representation being a digital re-presentation of utility usage information from a single utility usage meter location; and, means for communicating the plurality of digital representations to a utility usage information utilization device;
whereby said system allows the monitoring of any of a plurality of remote utility meters selectively under the control of a computer of any ON-HOOK telephone line without the necessity of dialing up any line.
2. Th utility meter reading system in accordance with Claim 1 in which the means at said central office for sending at least one distinct interrogation signal, means at said central office for receiving the plurality of alternating current representations, means for converting the alternating current representations into digital representations and the means for communicating the digital representations to the utility usage information utilization device comprise a transceiver device coupled to said multiplexer means which includes a means for storing at least one of the digital representations in a digital representation system.
3. The utility meter reading system in accordance with Claim 1 in which said interface means generates the alternating current representations comprising a series of dual-tone signals which represent a utility usage figure and a meter identification figure, there being at least twelve distinct dual-tone signals, each distinct dual-tone signal representing the following: a digit value between and including 0 to 9, a first framing sentinel and a second framing sentinel.
4. A method of sending utility usage information over a plurality of telephone lines comprising the steps of:
direct current and alternating current coupling at least one meter interface device to each of the telephone lines, each of the meter interface devices being coupled to at least one utility usage meter for receiving usage information therefrom and for sending alternating current representations of the usage information over its discrete telephone line responsive to receiving at least one distinct alternating current interrogation signal from its discrete telephone line;
continuously powering the interface device during ON-HOOK conditions by ON-HOOK current on the telephone line;
multiplexing said alternating current representations of usage information and interrogation signals;
sending at least one distinct alternating current interrogation signal over each of the plurality of telephone lines;
receiving the plurality of alternating current representations of the usage information;
converting the alternating current representations into a plurality of digital representations, each digital representation being a digital representation of usage information from a single utility usage monitor; and communicating the plurality of digital representations to a utility usage information utilization device.
direct current and alternating current coupling at least one meter interface device to each of the telephone lines, each of the meter interface devices being coupled to at least one utility usage meter for receiving usage information therefrom and for sending alternating current representations of the usage information over its discrete telephone line responsive to receiving at least one distinct alternating current interrogation signal from its discrete telephone line;
continuously powering the interface device during ON-HOOK conditions by ON-HOOK current on the telephone line;
multiplexing said alternating current representations of usage information and interrogation signals;
sending at least one distinct alternating current interrogation signal over each of the plurality of telephone lines;
receiving the plurality of alternating current representations of the usage information;
converting the alternating current representations into a plurality of digital representations, each digital representation being a digital representation of usage information from a single utility usage monitor; and communicating the plurality of digital representations to a utility usage information utilization device.
5. The method of sending utility usage information over a plurality of telephone lines comprising the steps of:
DO and A.C. coupling at least one meter interface device to each of the telephone lines, each of the meter interface devices being coupled to at least one utility usage meter for receiving usage information therefrom and for sending alternating current representations of the usage information over its discrete telephone line responsive to receiving at least one distinct alternating current interrogation signal from its discrete tele-phone line;
continuously powering the interface device by ON-HOOK
current on the telephone line;
multiplexing said alternating current representations of usage information and interrogation signals;
sending at least one distinct alternating current interrogation signal over each of the plurality of telephone lines;
receiving the plurality of alternating current representations of the usage information;
converting the alternating current representations into a plurality of digital representations, each digital representation being a digital representation of usage information from a single utility usage monitor; and communicating the plurality of digital representations to an external digital interfacing device;
in which the alternating current representations com-prise a series of dual-tones, each dual tone representing at least a single digit value between and including 0 and 9 and a first and second framing sentinel.
DO and A.C. coupling at least one meter interface device to each of the telephone lines, each of the meter interface devices being coupled to at least one utility usage meter for receiving usage information therefrom and for sending alternating current representations of the usage information over its discrete telephone line responsive to receiving at least one distinct alternating current interrogation signal from its discrete tele-phone line;
continuously powering the interface device by ON-HOOK
current on the telephone line;
multiplexing said alternating current representations of usage information and interrogation signals;
sending at least one distinct alternating current interrogation signal over each of the plurality of telephone lines;
receiving the plurality of alternating current representations of the usage information;
converting the alternating current representations into a plurality of digital representations, each digital representation being a digital representation of usage information from a single utility usage monitor; and communicating the plurality of digital representations to an external digital interfacing device;
in which the alternating current representations com-prise a series of dual-tones, each dual tone representing at least a single digit value between and including 0 and 9 and a first and second framing sentinel.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/543,372 US4578536A (en) | 1983-10-19 | 1983-10-19 | Centerpoint automatic meter reading system |
| US543,372 | 1983-10-19 |
Publications (1)
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|---|---|
| CA1228184A true CA1228184A (en) | 1987-10-13 |
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| CA000465718A Expired CA1228184A (en) | 1983-10-19 | 1984-10-18 | Centerpoint automatic meter reading system |
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| US7831204B1 (en) | 1981-11-03 | 2010-11-09 | Personalized Media Communications, Llc | Signal processing apparatus and methods |
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-
1983
- 1983-10-19 US US06/543,372 patent/US4578536A/en not_active Expired - Lifetime
-
1984
- 1984-10-17 WO PCT/US1984/001663 patent/WO1985001852A1/en not_active Application Discontinuation
- 1984-10-17 EP EP19840903869 patent/EP0159351A4/en not_active Withdrawn
- 1984-10-17 BR BR8407129A patent/BR8407129A/en unknown
- 1984-10-17 AU AU35081/84A patent/AU3508184A/en not_active Abandoned
- 1984-10-17 JP JP59503826A patent/JPS61500399A/en active Pending
- 1984-10-18 CA CA000465718A patent/CA1228184A/en not_active Expired
- 1984-10-19 IT IT23257/84A patent/IT1175882B/en active
- 1984-10-19 ES ES536957A patent/ES8606695A1/en not_active Expired
- 1984-10-21 IL IL73274A patent/IL73274A0/en unknown
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| AU3508184A (en) | 1985-05-07 |
| EP0159351A4 (en) | 1986-03-18 |
| WO1985001852A1 (en) | 1985-04-25 |
| US4578536A (en) | 1986-03-25 |
| ES8606695A1 (en) | 1986-04-16 |
| ES536957A0 (en) | 1986-04-16 |
| EP0159351A1 (en) | 1985-10-30 |
| IT8423257A1 (en) | 1986-04-19 |
| IT8423257A0 (en) | 1984-10-19 |
| JPS61500399A (en) | 1986-03-06 |
| IL73274A0 (en) | 1985-01-31 |
| BR8407129A (en) | 1985-10-08 |
| IT1175882B (en) | 1987-07-15 |
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