Abstract:
A network of fixed RF transmitter modules, an RF repeater module and an RF collector module are located within a multi-unit facility for collecting water usage data from a plurality of water meters associated with the units within the facility and for uploading to a central billing center. Each water meter is coupled to a single RF transmitter module. Each RF transmitter module reads the water meter multiple times per day and transmits the data over a 418 MHZ carrier. One of a plurality of transceivers coupled to the RF repeater module receives the data and directs it to a storage medium in the RF repeater module. The RF repeater module temporarily holds the data and then repeats it on the RF carrier. The RF collector module receives the data through a transceiver coupled thereto. The data is stored in a storage medium of the RF collector module for retrieval by the central billing center.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a system for remote reading of utility meters. More particularly, it relates to an automatic electronic system for remote reading of water utility meters in a multi-unit facility employing RF signals to transmit the data read to a central location. 
     2. Description of Prior Art 
     The use of RF signals to transmit data from a remote to a central location is well known in the prior art. Further, the use of RF signals to transmit utility meter data (i.e., electricity, gas and water meters) is also well known. For instance, U.S. Pat. No. 3,688,271 to Rouse discloses a method and apparatus for transmitting utility meter data from a single consumer meter to a mobile command unit utilizing RF signals. The Rouse system includes the mobile command unit which must initiate the consumer meter through the transmission of a unique I.D.—a so called “wake-up” procedure. Although the Rouse system was an improvement over the existing prior art in that a utility company employee is not required to personally inspect each consumer meter and to physically note the meter readings, the invention lacks automatic reading features and is not considered a “pure” remote reading system. 
     Improvement in the art can been seen in U.S. Pat. No. 4,940,976 to Gastouniotis et al. and U.S. Pat. No. 5,448,230 to Schanker et al. Each system attempts to provide an enhanced automatic system for reading data from utility meters and sending it to a central location. But, neither these references nor any other references in the prior art disclose or teach the novel aspects of the present invention. In particular, nothing in the prior art alone or in combination teaches or discloses a fully automatic remote utility meter data reading system of a fixed network capable of reading a plurality of meters automatically and transmitting that data to single collector unit by means of a single RF carrier. 
     SUMMARY OF THE INVENTION 
     In multi-unit residential facilities, such as apartment buildings, there is a need for individual unit metering of the utilities provided to the apartment dwellings. This permits the management or owner of the multi-unit complex to charge each individual apartment dweller the exact amount for their consumption of the respective utility. Without such capability, the management or owner must estimate the utility usage for the entire apartment complex for a whole year and attempt to spread the estimated cost among all the apartment dwellers by charging a percentage per month in the rent cost upon signing the lease with the apartment dweller. More particularly, due to the increasing costs and shortages of water throughout the country and the world, a system for permitting exact allocation of water usage is greatly needed. 
     The present invention addresses and solves the problems seen in multi-unit facility utility consumption by providing a fully automatic remote meter data reading system capable of reading individual meters of each unit and transmitting the read data to a single collection device by means of a single RF carrier. 
     The present invention contains a plurality of transmitters having microprocessor controlled circuits. The number of transmitters is directly proportional to the number of utility meters which is in turn directly proportional to the number of apartments within the multi-unit facility. The transmitter is capable of entering a low power consumption mode when not reading the meter. Upon powering up, the transmitter reads the meter and transmits its read via a single RF carrier. A single microprocessor controlled repeater, mounted within the apartment complex, receives the multiple transmitter send a single or plurality of transceivers coupled thereto. The repeater holds the data for a short time period and then re-transmits, or repeats, the data through one of the coupled transceivers to a microprocessor controlled collector device. The collector device also has a single transceiver coupled thereto for receiving data along the RF carrier signal. Various interfaces in the collector allow it to receive data or instructions from the transceiver, a remote computer via a modem, or a direct link to a local PC. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention may be best understood by those having ordinary skill in the art by reference to the following detailed description when considered in conjunction with the accompanying drawings in which: 
     FIG. 1 is a graphical representation of an environment in which the present invention is employed; 
     FIG. 2 is a partial schematic diagram of an electrical circuit of a meter read transmitter device employed in the system of the present invention; 
     FIG. 2.1 is a partial schematic diagram of an electrical circuit of a meter read transmitter device as shown in connection with FIG. 2; 
     FIG. 2.2 is a partial schematic diagram of an electrical circuit of a meter read transmitter device as shown in connection with FIGS.  2 - 2 . 1 ; 
     FIG. 3 is a partial schematic diagram of an electrical circuit of a transceiver device for separately coupling to a repeater device and a collector device both employed in the system of the present invention; 
     FIG. 3.1 is a partial schematic diagram of an electrical circuit of a transceiver device for separately coupling to a repeater device and a controller device as shown in connection with FIG. 3; 
     FIG. 3.2 is a partial schematic diagram of an electrical circuit of a transceiver device for separately coupling to a repeater device and a controller device as shown in connection with FIGS.  3 - 3 . 1 ; 
     FIG. 4A is a partial first portion of a schematic diagram of an electrical circuit of the repeater device; 
     FIG. 4A.1 is a partial first portion of a schematic diagram of an electrical circuit of the repeater device as shown in connection with FIG. 4A; 
     FIG. 4A.2 is a partial first portion of a schematic diagram of an electrical circuit of the repeater device as shown in connection with FIGS.  4 A- 4 A. 1 ; 
     FIG. 4B is a partial second portion of the schematic diagram of the electrical circuit of the repeater device; 
     FIG. 4B.1 is a partial second portion of the schematic diagram of the electrical circuit of the repeater device as shown in connection with FIG. 4B; 
     FIG. 4C is a partial third portion of the schematic diagram of the electrical circuit of the repeater device; 
     FIG. 4C.1 is a partial third portion of the schematic diagram of the electrical circuit of the repeater device as shown in connection with FIG. 4C; 
     FIG. 5A is a partial first portion of a schematic diagram of an electrical circuit of the collector device; 
     FIG. 5A.1 is a partial first portion of a schematic diagram of an electrical circuit of the collector device as shown in connection with FIG. 5A; 
     FIG. 5A.2 is a partial first portion of a schematic diagram of an electrical circuit of the collector device as shown in connection with FIGS.  5 A- 5 A. 1 ; 
     FIG. 5B is a partial second portion of the schematic diagram of the electrical circuit of the collector device; 
     FIG. 5B.1 is a partial second portion of the schematic diagram of the electrical circuit of the collector device as shown in connection with  5 B; 
     FIG. 5B.2 is a partial second portion of the schematic diagram of the electrical circuit of the collector device as shown in connection with FIGS.  5 B- 5 B. 1 ; 
     FIG. 5C is a partial third portion of the schematic diagram of the electrical circuit of the collector device; 
     FIG. 5C.1 is a partial third portion of the schematic diagram of the electrical circuit of the collector device as shown in connection with FIG. 5C; 
     FIG. 5D is a partial fourth portion of the schematic diagram of the electrical circuit of the collector device; 
     FIG. 5D.1 is a partial fourth portion of the schematic diagram of the electrical circuit of the collector device as shown in connection with FIG. 5D; 
     FIG. 6A is a block logic diagram of a main program carried out by a microprocessor of the meter read transmitter device; 
     FIG. 6B is a block logic diagram of a manual switch interrupt program carried out by the microprocessor of the meter read transmitter device; 
     FIG. 7A is a block logic diagram of a main program carried out by a microprocessor of the repeater device; 
     FIG. 7B is a block logic diagram of a receive character interrupt program carried out by the microprocessor of the repeater device; 
     FIG. 8A is a block logic diagram of a main program carried out by a microprocessor of the collector device; 
     FIG. 8B is a block diagram of a receive character interrupt program carried out by the microprocessor of the collector device; and 
     FIG. 8C is a block logic diagram of a modem ring-receive interrupt program carried out by the microprocessor of the collector device. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Throughout the following detailed description, the same reference numerals refer to the same elements in all figures. 
     Referring to FIG. 1, a graphic representation of the present invention is shown wherein a plurality of transmitters  10 , a single repeater  12  and a single collector  14  are provided. The number of transmitters  10  is directly proportional to the number of water meters  16  used in a multi-unit complex which in turn is directly proportional to the number of apartment units within the complex. For instance, if there are fifty apartment units, there would be fifty separate water meters  16  and hence fifty separate transmitters  10 . 
     Each transmitter  10  has a 50 ohm matched antennae  18  coupled to an electrical circuit  20  of transmitter  10 . As shown in FIGS.  2 - 2 . 2 , antennae  18  is coupled to an RF output, at pin  5 , of an LC series transmitter module  22 . In the preferred embodiment, a Linx Technology TXM-418-LC transmitter module is used. This type of module transmits serial data at 418 MHZ, the frequency used in the system of the present invention to transmit water meter read data from transmitter  10  to repeater  12  and then again to collector  14 . Transmitter module  22  transmits its serial data using CPCA (Carrier-Present, Carrier-Absent) modulation—also referred to as OOK (On-Off Keyed). This type of AM modulation represents a logic low ‘0’ by the absence of a carrier, zero output power, and a logic high ‘1’ by the presence of a carrier. 
     Further to FIGS.  2 - 2 . 2 , transmitter module  22  is an eight pin, hybrid SMD module. Pins  1 ,  3 ,  4 ,  6  and  8  are all tied to ground. Pin  2 , data in, is coupled to pin  17  of a microcontroller  24  of transmitter circuit  20  and pin  7 , positive supply Vcc, is coupled to a power supply through a supply filter. In circuit  20 , the supply filter includes a 10 ohm resistor R 5  in series with the power supply followed by a 10 uF capacitor from Vcc to ground. The supply filter ensures a clean, well-regulated power source to module  22  in cases where the quality of the power supply source becomes degraded. 
     With continuing reference to FIGS.  2 - 2 . 2 , circuit  20  employs microcontroller (PIC)  24 , additionally designated as U 3  in circuit  20 . In the preferred embodiment, a Microchip Technology PIC16LC54A, 8-bit, fully static, EPROM/ROM-based CMOS, eighteen pin, twelve I/O port, microcontroller is employed. The eighteen pins are coupled to other components of circuit  20  in the following manner: pin  1  (RA 2 ) to a first end of an optoisolator circuit (to be discussed in further detail hereinafter), pin  2  (RA 3 ) to a optional LED circuit, pin  3  (T 0 CKI) floats, pin  4  (MCLR) to the power supply (Vcc), pin  5  to ground (not shown), pin  6  (RB 0 ) to chip enable of a real time clock  26  (to be discussed in further detail hereinafter), pin  7  (RB 1 ) to serial clock of real time clock  26 , pin  8  (RB 2 ) to serial data in of real time clock  26 , pin  9  (RB 3 ) to serial data out of real time clock  26 , pins  10 - 13  (RB 4 - 7  respectively) float, pin  14  (not shown) to the power supply (Vcc), pins  15  and  16  (OSC 1  and OSC 2  respectively) to a 4 MHZ crystal, pin  17  (RA 0 ) to data in of transmitter module  22  and pin  18  (RA 1 ) to a second end of the optoisolator circuit. 
     With continuing reference to FIGS.  2 - 2 . 2 , the optional LED circuit, coupled to pin  2  of PIC  24 , permits an installer of the system to verify that the installation of the transmitter is proper. The optoisolator circuit is coupled between PIC  24  and water meter  16 . In the preferred embodiment, an encoder type water meter is used, although the system of the present invention could be modified to interface with a pulsar type meter. Each encoder meter has three leads—R, G and B. In the preferred embodiment, R is the clock line, G is the data line and B is ground. The optoisolator circuit includes a single transistor type multi optocoupler and a plurality of resistors. In the preferred embodiment, an NEC PS2501-2 is employed for the multi-optocoupler. As shown in FIG. 2, pin  1  of the multi-optocoupler is coupled through a resistor to the power supply (Vcc). Pin  2  is coupled to pin  18  of PIC  24 . Pin  3  is coupled through a resistor to Vcc 5 v. Pin  4  is coupled to ‘G’ on water meter  16 . Pin  5  is coupled to ground. Pin  6  is coupled to a line connecting pin  1  of PIC  24  to the power supply (Vcc). Pin  7  is coupled to ‘R’ on water meter  16 . Pin  8  is coupled to Vcc 5 v. Vcc 5 v, provided by a voltage doubler of circuit  20 , is used to activate meter  16  and permit a read thereupon by circuit  20 . The optoisolator circuit provides electrical isolation between the water meter and the transmitter circuitry. 
     With continuing reference to FIGS.  2 - 2 . 2 , it is shown that a voltage doubler circuit is employed within transmitter electrical circuit  20 . The voltage doubler circuit employs a monolithic CMOS voltage conversion IC, designated by the symbol U 1 , a pair of capacitors, C 1  and C 2 , and a pair of diodes, D 1  and D 2 . In the preferred embodiment, a Harris Semiconductor ICL7660S super voltage converter (eight pin plastic DIP) is used for the voltage conversion IC. C 1  and C 2  are 10 uF capacitors and D 1  and D 2  are Liteon 1N4002CT diodes. The voltage divider circuit provides positive voltage doubling to electrical circuit  20 . In particular, the pump inverter switches of U 1  are used to charge C 1  to a voltage level of Vcc minus Vdiode, where Vcc is the supply voltage and Vdiode is the forward voltage on C 1  plus the supply voltage. This voltage level is applied through D 2  to capacitor C 2 . The voltage thus created on C 2  becomes 2(Vcc) −2(Vdiode) or twice the supply voltage minus the combined forward voltage drops of D 1  and D 2 . In the preferred embodiment, a 3.6 voltage battery is used as the supply voltage or Vcc. Since there is a 0.6 v drop across each diode, the resulting doubled voltage becomes approximately 5 v, or 2(3.6) −2(0.6) =6.0 v. It is noted that pin  6  or LV is left floating to prevent device latchup. 
     With further reference to FIGS.  2 - 2 . 2 , it shown that a real time clock (RTC)  26  is employed in transmitter electrical circuit  20 . In the preferred embodiment, a Dallas Semiconductor DS 1305 , serial alarm real time clock is used, additionally designated in circuit  20  as U 5 . RTC  26  is configured to a “battery operate mode” wherein RTC  26  is powered by a 3.6 v single cell battery. Accordingly, Vcc 1  and Vbat (pins  16  and  2  respectively) of RTC  26  are tied to ground while Vcc 2  (pin  1 ) is coupled to the 3.6 v battery source. RTC  26  is capable of operating in two distinct serial interface modes. In the preferred embodiment, RTC  26  utilizes the Motorola Serial Peripheral Interface (SPI), wherein VccIF (pin  14 ) is tied to the SERMODE pin (pin  9 ). Four pins are used for the SPI: CE, SCLK, SDI and SDO. SDI and SDO (pins  12  and  13  respectively) are the serial data input and output pins for RTC  26 , respectively. CE is used to initiate and terminate a data transfer between RTC  26  and PIC  24 . SCLK is used to synchronize data movement between the master (PIC  24 ) and the slave (RTC  26 ). X 1  and X 2  (pins  3  and  4 , respectively) are coupled to a 32.768 KHz quartz crystal. INTO (pin  6 ), an active low, is used as an interrupt input to PIC  24 . As shown in FIG. 2, INTO is coupled to an auxiliary initiation circuit which includes, inter alia, a magnetic switch S 1  and a ZVP4105A P-Channel MOSFET Q 1 . Since INTO is an open drain output, it requires an external pull-up resistor, which is shown as R 2 , a 47K ohm resistor tied to Vbat. A 100K ohm resistor R 12  and a 0.01 uF capacitor C 9  coupled in parallel to ground provides a buffer for the auxiliary initiation circuit. 
     With continuing reference to FIGS.  2 - 2 . 2 , a shield bead L 1  is shown and is tied between analog and digital grounds of circuit  20 . Shield bead Li acts as a high frequency noise filter for keeping digital noise off the RF ground. 
     Once meter  16  is read, the data is transmitted from transmitter  12  on the 418 MHZ RF carrier to repeater  12 . A plurality of transceivers  28  are coupled to repeater  12  for receiving the RF carrier frequency and for transmitting that same water meter data to collector  14  after an elapsed time period. In the preferred embodiment, up to five transceivers  28  are coupled to repeater  12 . It is understood that in small systems, repeater  12  can be removed whereby transmitters  10  transmit their data directly to collector  14 . 
     Referring to FIGS.  3 - 3 . 2 , an electrical circuit  30  is shown representing the electrical circuitry of transceiver  28 . Power is supplied to transceiver  28  from an interface with repeater  12 . In the preferred embodiment, a six conductor, category  5  cable is used for the interface between transceiver  28  and repeater  12 . Connections P 1 - 4  and P 7 - 8  represent the six conductor connection points for circuit  30  to repeater  12 . In an alternate embodiment, an RS422 interface is employed wherein connection with repeater  12  is made at J 1  of circuit  30 . In each embodiment, an unregulated 11 v is supplied to transceiver  28  at P 7 , or J 1  pin  7 , from a power supply of repeater  12  (not shown). A voltage regulation circuit, including, inter alia, a three terminal positive voltage regulator, is coupled to the unregulated 11 v supply voltage for converting the unregulated supply to a regulated 5 v. In the preferred embodiment, a Motorola MC78M05CDT regulator is employed. The regulated 5 v is supplied to four ICs of circuit  30 . 
     With continuing reference to FIGS.  3 - 3 . 2 , an LC series receiver module  32  is provided in circuit  30 . In the preferred embodiment, a Linx RXM-418-LC receiver module is employed. Module  32  is a ten pin IC designed to recover data sent by a CPCA transmitter. Module  32  is configured such that pin  1 , RF data in, is coupled to an antenna  34 , pins  2 ,  4 ,  7 ,  9  and  10  float, pins  3  and  8  (internally connected) are both tied to ground, pin  5 , data out, is coupled to a driver output enable and driver input pin of a transceiver IC (to be discussed in further detail hereinafter), pin  6 , positive supply Vcc for voltages in the range of 4.2-5.2 vDC is coupled to ground through a capacitor and to the regulated 5 v through a resistor (the resistor and capacitor arrangement representing a supply filter for Vcc pin  6 ). 
     With continuing reference to FIGS.  3 - 3 . 2 , a transceiver IC  36  is provided. In the preferred embodiment, a Maxim 483CSA, RS485/RS422, eight pin, half duplexing, transceiver IC is employed. Transceiver  36  is configure such that pin  1 , RO floats, pin  2 , RE is coupled to pin  8 , Vcc which in turn are both coupled to the regulated positive 5 v supply, pins  3  and  4 , DE and DI respectively, both receive data out from receiver module  32 , pin  5  is tied to ground and pins  6  and  7 , A and B respectively, representing RXA and RXB respectively are coupled to interface connection points  3  and  4  respectively, which are coupled to repeater  12 . 
     Data received by transceiver  28  is supplied to repeater  12  and held for a duration of time. Upon a routine (to be discussed in further detail hereinafter), the data received by repeater  12  is re-transmitted, or repeated, to collector  14 . Accordingly, the meter read data is supplied to transceiver  28  from repeater  12  for transmission to collector  14 . As shown in FIGS. 3.1 and  3 . 2 , connection points  1  and  2  of the interface receive the data from repeater  12  and represent TXA and TXB respectively. TXA and TXB are coupled to inverting and non-inverting receiver inputs, pins  7  and  8  respectively, of a transceiver IC  38 . In the preferred embodiment, transceiver  38  is a Maxim 488CSA, RS485/RS422, eight pin, full duplexing, transceiver IC. The remaining six pins are configured such that pin  1 , Vcc is coupled to the regulated positive 5V supply, pin  2 , RO or receiver output, is coupled to data in of a transmitter module  40 , pins  3 ,  5  and  6  float and pin  4  is tied to ground. 
     With continuing reference to FIGS.  3 - 3 . 2 , data outputted from transceiver  38  is supplied to transmitter module  40 . In the preferred embodiment, a Linx TXM-418-LC series transmitter is employed. Transmitter module  40  has an antenna  42  coupled to an RF out (pin  5 ) for transmitting the 418 MHZ RF carrier frequency to collector  14 . Pin  7  of module  40  is coupled to the regulated positive 5V supply and all remaining pins are tied to ground. 
     With reference now to FIGS.  4 A- 4 C. 1 , an electrical circuit  44  is shown representing the circuitry of repeater  12 . It is understood that the circuitry is “pieced” together by connecting the various circled points A, B and C. For instance, by following the four points on FIG. 4A.2 represented by the circled letter B leads to the circuitry shown in FIG. 4B wherein circled A connects to circled B. 
     As shown in FIG. 4C, received meter read data from interface connection points  3  and  4  is inputted to a transceiver module  46  at ports A and B, pins  8  and  7  respectively of module  46 . The data received therein is outputted at pin  2 , RO or receiver output, to a microcontroller  48  at pin  10 , designated as RXDO or the serial data input port. In the preferred embodiment, transceiver  46  is a Maxim 488CSA, RS-485/RS422, eight pin, full duplexing, transceiver IC and microcontroller  48  is a Phillips Semiconductors 80C32 8-bit,  40  pin, microcontroller. 
     Further to the circuitry of repeater  12 , and as shown in FIGS.  4 C- 4 C. 1 , a second transceiver module  50  is employed in circuit  44 . Module  50  is coupled to data receive lines ‘A’ and ‘B’ and drives the receive lines low when transceivers  28  are not receiving data from transmitters  10 . In the preferred embodiment, a Maxim 488CSA, RS-485/RS422, eight pin, full duplexing, transceiver IC is used for module  50 . 
     Referring to FIGS.  4 A- 4 A. 2  and  4 B- 4 B. 1 , it is shown that additional components are employed in circuit  44 . In particular, octal latches  52 , timekeeper SRAM  54  and optional EPROM  56  are employed to operate circuit  44 . 
     Referring to FIGS.  5 A- 5 D. 1 , an electrical circuit  58  is shown representing the circuitry of collector  14 . It is understood that the circuitry is “pieced” together by connecting the various circled points A, B and C. For instance, by following the four points on FIG. 5A.2 represented by the circled letter B leads to the circuitry shown in FIG. 5B.2 wherein circled A connects to circled B. 
     Collector  14  receives RF data from a transceiver  28  which is identical to the transceivers used with repeater  12 . The RF data received by the collector transceiver is transmitted from one of the repeater transceivers. In the preferred embodiment, the collector transceiver interfaces with collector  14  via an RS422 interface connection using RJ45, six conductor, category 5 cabling. As shown in FIGS.  5 D- 5 D. 1 , meter read data received by the collector transceiver is directed to interface J 2  at connection points  3  and  4  and is inputted to a transceiver module  60  at ports A and B, pins  8  and  7  respectively of module  60 . The data received therein is outputted at pin  2 , RO or receiver output, to a microcontroller  62  at pin  10 , designated as RXDO or the serial data input port. In the preferred embodiment, transceiver  60  is a Maxim 488CSA, RS-485/RS422, eight pin, full duplexing, transceiver IC and microcontroller  62  is a Phillips Semiconductors 80C32 8-bit,  40  pin, microcontroller. 
     Further to the circuitry of collector  14 , and as shown in FIG. 5D, a second transceiver module  64  is employed in circuit  58 . Module  64  is coupled to data receive lines ‘A’ and ‘B’ and drives the receive lines low when the collector transceiver is not receiving data. In the preferred embodiment, a Maxim 488CSA, RS485/RS422, eight pin, full duplexing, transceiver IC is used for module  64 . 
     Referring to FIGS.  5 A- 5 D. 1 , is shown that collector electrical circuit  58  is almost identical to repeater electrical circuit  44  except for additional components employed with collector  14 . Accordingly, collector  14  employs octal latches  66 , timekeeper SRAM  68  and optional EPROM  70 . In addition, collector electrical circuit  58  employs 512K of flash memory  72 , a driver/receiver level translator  74  for an RS232 interface, an analog data select  76  and a modem (not shown). 
     In the preferred embodiment, the system of the present invention operates under rules defined by the FCC in Part  15 . A 20 dB relaxation on the power limitations is allowed if a duty cycle, or the on/off ratio, is 10% or less for any 100 millisecond transmission. To meet this requirement, the transmitter and repeater of the present system follow a certain novel protocol. First, the amount of data being transmitted is fixed and therefore the duration of each transmission is fixed—this duration always being less than one second. Secondly, the duty cycle, over any 100 millisecond period, is always less than 10%. This is guaranteed by the novel encoding scheme used by the system. In particular, each transmission consists of a maximum of 226 “on” pulses—226 being a theoretical maximum which is not realized in actual use, but is entertained to derive worst-case conditions. The duration of each pulse is approximately 250 microseconds (this being dependant on the tolerance of the oscillator, which is 5%). There is a 50 millisecond blanking period after each 16 pulses; no pulses are transmitted during the blanking period. Accordingly, the maximum number of pulses during a 100 millisecond period would be two 16-bit pulse trains, or 32 pulses. At 250 microseconds per pulse, this amounts to a total “on” time of 8 milliseconds. Thus, the duty cycle is 8%. 
     Further to the novel protocol used in transmissions in the present invention, transmitters  10  transmit every 6 to 7 hours. The exact period is randomized, but never less than 6 hours and never more than seven hours. Repeater  12  will not transmit more than once per thirty-one (31) second period, thereby satisfying certain Part  15  requirements that the silent period between transmissions must be thirty (30) times the duration of the transmission. This thirty-one (31) second period is guaranteed by instructions carried out by novel firmware in repeater  12 , in conjunction with its internal real time clock. 
     Referring to FIG. 6A, a flow diagram is shown representing the main program of transmitter  10 . Assuming for now that transmitter  10  has been properly installed and initialized, microcontroller  24  of transmitter  10  is first powered. The powering of microcontroller  24  can be accomplished either through manual initiation (to be discussed in further detail hereinafter) or by real time clock (RTC)  26 . Once microcontroller  24  is awake, it pulses meter  16  from RA 1 , or pin  18 , of microcontroller  24  through the optoisolator circuit to the ‘R’, or clock, line of meter  16 . By bringing the clock line high, the meter puts a binary 0 or 1 on the data line; thereafter, the clock line is brought low and the bit on the data line is read. Once a byte (7 bits of data and an eighth parity bit) of data is read and it is determined that the read is successful, the meter read data is outputted to transmitter module  22  from RAO, or pin  17 , of microcontroller  24  to data in, or pin  2 , of module  22 . Immediately thereafter the data is transmitted over the RF link—the 418 MHZ carrier frequency. If the read is unsuccessful, microcontroller  24  will load the meter ID from non-volatile memory (EPROM of RTC  26 ). At this point, microcontroller  24  will not attempt another read. Instead the meter ID would then be transmitted along with an error code in the form of decimal number “2” for “meter not connected.” Decimal number “2” is one of three error codes potentially embedded in a status byte of the transmitted data. Decimal number “2” represents the particular error code for a bad meter read. 
     The data to be transmitted is a 15 byte data string. Byte  1  is the STX (Start of Text) character; Byte  2  is the Status Code of Meter; Bytes  3 - 6  are the Meter Value; Bytes  7 - 14  are the Meter ID; and Byte  15  is the Checksum. However, in order to employ an averaging technique allowed by the FCC (and thereby gain additional allowed power), each byte is encoded into eight bytes, except for Byte  1  (the STX character), which is not encoded. Thus, in actuality 113 bytes are transmitted over the RF link (14×8=112 bytes plus the STX character byte for a total of 113 bytes of transmitted data). 
     With continuing reference to FIG. 6A, once a successful meter read data has been transmitted, microcontroller  24  generates a random number between 0 (zero) and 59 (fifty-nine). This random number is added to 5:00 am to create a time between 5:00 am and 5:59 am. The RTC  26  clock is then set to this “created time” and the RTC alarm is set to 12 noon. The RTC alarm interrupt line is then reset to high thereby placing a high on the gate of FET Q 1  high which results in cutting off power to microcontroller  24 . Once power is cut off to microcontroller  24 , transmitter  10  waits until the six to approximately seven hour “created time” elapses whereafter the RTC alarm goes off and RTC  26  once again powers-up microcontroller  24  so that another read upon meter  16  can be taken for subsequent transmission over the RF link. The powering down of microcontroller  24  ensures a longer life for the battery used in transmitter  10  of seven to ten years with some results indicating a life potential of fifteen years. 
     Referring to FIG. 6B, a flow diagram of a sub-program is shown representing the steps used for an initialization procedure or manual operation of transmitter  10 . In regards to the initialization procedure, when the system is first installed, each transmitter  10  is coupled to a specific meter and has a unique meter ID burned into non-volatile memory of transmitter  10 . Thereafter the transmitter is checked for proper operation. The sub-program of FIG. 6B accomplishes these objectives. A magnetic switch Si (see FIG.  2 ), coupled to pin  6 , or INTO, of RTC  26 , is normally an open circuit. By manually placing a magnet thereover, magnetic switch S 1  closes causing microprocessor  24  to be powered and the RTC oscillator and alarm to be enabled, causing the LED to blink and microcontroller  24  to read meter  16  and transmit the data as above by the main program of FIG.  6 A. If the switch is still closed by the magnet, the main program will jump to the sub-program prior to the main program end and repeat the cycle until the watchdog timer resets microprocessor  24 . The result is that the LED will blink for approximately 3 seconds and transmit the meter ID and data read and will repeat as long as the switch is closed and/or the magnet is in place. Once the magnet is removed the main program will end after having set the RTC time and alarm as in the standard mode of transmission. The magnet can also be used to manually transmit the meter data as above in an installation mode. 
     Referring to FIG. 7A, a flow diagram is shown representing the main program of repeater  12 . Assuming a message (meter read data obtained by transmitter  10 ) has been received by at least one of the transceivers  28  over the RF link and directed to repeater  12  through the Receive Interrupt Routine of FIG. 7B, a query is made asking whether a message needs to be repeated (a flag is set in the interrupt routine indicating that the message needs to be repeated). If no, the program loops around and asks again whether there is a message to repeat. When the answer is yes, repeater  12  reads the current time from its RTC, checks the “repeat time” in seconds (generated in the Receive Interrupt Routine) and compares it to the seconds of the current time. A query is then made asking whether the “repeat time” has been satisfied. If yes (the FCC required 30 seconds has elapsed from a previous transmission and the current time and “repeat time” seconds match for this message), the message is transmitted, or repeated, to collector  14  or another repeater  12 . Thereafter, the message&#39;s repeat message flag is cleared therefrom, indicating that the message has been repeated. Messages having a cleared flag will not be repeated. It is noted that the same encoding scheme is used as described hereinabove in reference to the data being transmitted from transmitter  10  to repeater  12 . 
     With continuing reference to FIG. 7A, if the “repeat time” is not satisfied, the repeat message flag remains and the message stays in the main program loop until the “repeat time” matches the current time “seconds” wherein it is thereafter transmitted. The “repeat time” represents a random delay of up to one minute and is generated when the message is first received by repeater  12 . The random delay is some number between 0 and 59 seconds. This minimizes the possibility of the two repeaters, placed in close proximity of one another, from receiving the same message and repeating it simultaneously, which would most likely result in corrupted transmissions. 
     Referring to FIG. 7B, a flow diagram is shown representing a Receive Interrupt Routine carried out by repeater  12 . The Receive Interrupt Routine relates to the steps carried out by repeater  12  as it receives a message directed from one of the plurality of transceivers  28  coupled thereto. When a character is received over the RF link, the Receive Interrupt Routine is entered. First, the character is added to a receive buffer. Next, a query is made asking whether a full message has been received (STX character byte plus 112 bytes). If the message is not a full message, the Receive Interrupt Routine is exited, returning repeater  12  to the main program of FIG.  7 A. If a full message has been received, the message is decoded from 113 bytes to 15 bytes (one STX character byte, thirteen bytes of meter data and the Checksum byte). Next, the received Checksum is calculated and matched against the transmitted Checksum. If the two Checksums do not match, the Receive Interrupt Routine moves to a point wherein the receive buffer is cleared and the interrupt routine is exited, returning repeater  12  to the main program of FIG.  7 A. If the two Checksums match, a query is made asking whether a message has been received from the same meter in the last sixty (60) minutes. If yes, the message is ignored and the Receive Interrupt Routine moves to the point where the receive buffer is cleared and the interrupt routine is exited, returning repeater  12  to the main program of FIG.  7 A. If no, (it&#39;s been longer than sixty minutes since a message has been received from the same meter), then the Meter ID, Status Code of Meter, Meter Value and the time the message was received by repeater  12  is added into non-volatile flash memory. Thereafter, the “repeat time” value is generated (see above) and the flag is attached to the message indicating that the message needs to be repeated, or transmitted to collector  14 . The receive buffer is then cleared and the interrupt routine is exited, returning repeater  12  to the main program of FIG.  7 A. 
     Referring to FIG. 8B, a flow diagram is shown representing one of two sub-programs carried out by collector  14 . In particular, FIG. 8B shows the steps carried out by a Receive Interrupt Routine of collector  14 . If a character is received over the RF link by transceiver  28  of collector  14 , the Collector Receive Interrupt Routine is entered wherein the character is first added to a receive buffer of collector  14 . A query is formed asking whether the message is a full message (STX byte plus 112 bytes). If it is not a full message, the Receive Interrupt Routine is exited, returning collector  14  to the main program of FIG. 8A (to be discussed in full detail hereinafter). If the message is a full message, it is decoded into a 15 byte string or the single STX byte, the thirteen bytes of meter data and the Checksum byte (as discussed above in the transmitted data format of transmitter  10 ). The Checksum is then calculated and a query is made asking whether the calculated Checksum and transmitted Checksum match. If no, the Receive Interrupt Routine moves to a point where the receive buffer is cleared and the routine is exited thereby returning the program to the main program of FIG.  8 A. If the Checksums match, then another query is made asking whether collector  14  has been configured to receive this meter ID (by addressing a look-up table in RAM memory of collector  14 ). If no (collector  14  is not supposed to receive transmissions from this particular meter), the interrupt routine moves to a point whereby the receive buffer is cleared and the interrupt routine is exited thereby returning to the collector main program of FIG.  8 A. If collector  14  is configured to receive messages from the particular meter, the Meter Value and Status Code of Meter is extracted from the 14 byte string and stored in non-volatile flash memory along with the time the message was received which is taken from the RTC in collector  14 . Finally, the receive buffer is cleared and the routine in exited to the collector main program of FIG.  8 A. It is noted that the most significant bit (MSB) of byte number  2  (the status byte) contains a source flag indicating where this particular message originated from—transmitter  10  or repeater  12 . In the preferred embodiment, the MSB is set to ‘0’ for a transmitter message and ‘1’ for a repeater message. It is further noted that the meter configuration query ensures that two or more collectors positioned in close proximity of one another avoid collecting data not intended therefor. For example, the meter configuration query precludes two collectors positioned across the street from each other, in two separate apartment complexes, from receiving data from the other complexes&#39; meters. It is even further noted that in the preferred embodiment, 512K of flash memory is employed permitting 1024 slots in flash memory to be employed for a total permissible allocation of memory space for one reading for 1024 transmitters in one system. 
     In a preferred method, a central database automatically calls collector  14  via a modem and downloads the collected meter data. In alternate methods, and when it is necessary to perform configuration routines, collector  14  can either interface directly (on-site) with a PC via an RS-232 connection, interface remotely with a PC utilizing a two way connection via a modem or be connected directly to a standard telephone for purposes of “ringing” the collector. As seen in electrical circuit FIGS.  5 C- 5 C. 1 , data select  76  is employed to distinguish the interfacing unit addressing collector  14  as either an RF signal, a modem connection or a direct RS-232 PC connection. In the preferred embodiment, an SGS Thompson CD4529BE data select chip is employed. 
     If microcontroller  24  senses a ring from the modem, the Modem Ring Interrupt Routine is entered, as seen in FIG.  8 C. The total number of rings from the modem is read and a “ring count” is set. Thereafter, the Modem Ring Interrupt Routine is exited thereby returning to the main program of FIG.  8 A. 
     Referring to FIG. 8A, the main program of collector  14  is shown. Upon a “ring count” being determined by the Modem Ring Interrupt Routine, a query is made asking whether the “ring count” is greater than zero. If no, the same query is made asking whether the “ring count” is greater than zero. This query continues to loop until the answer becomes yes. Upon the “ring count” being greater than zero, or yes, a second query is made asking whether it has been more than ten seconds since the last ring. If yes (meaning the preprogrammed number of rings has polled collector  14  and the billing center is requesting the meter data), a query is made asking whether the “ring count” is greater than eight. If no (for instance, only five rings have been received), the “ring count” is reset to zero and the main program returns to the point wherein it is asked whether the “ring count” is greater than zero (or in other words, the point where the program is waiting to have a “ring count” set by the Modem Ring Interrupt Routine). If it has been greater than ten seconds since the last ring and the “ring count” is greater than eight (a ring initiation has been determined), collector  14  dials up the billing center using a preprogrammed telephone number, establishes a connection with the billing center and uploads all of its collected meter data. The ring initiation value can be changed to any number desired by the programmer/administrator of the system. Eight rings is used for illustrative purposes but does represent the value used in the preferred method of operation. After uploading all the meter readings, the “ring count” is reset to zero and the main program returns to the point wherein it is waiting to have a “ring count” set by the Modem Ring Interrupt Routine. 
     With continued reference to FIG. 8A, and at the point of the main program wherein it is asked whether it has been more than ten seconds since the last ring, and the answer is no (the phone is still ringing), a query is made asking whether the “ring count” is greater than twenty. If no, the program returns to the point wherein it is asked whether the “ring count” is greater than zero. If yes (“ring count” is greater than twenty), collector  14  answers the call and attempts to negotiate a connection with the calling modem. This function is primarily used for a two-way connection with a PC to remotely configure the system or to download specific information at the particular point in time of the two-way connection. A query is next made asking whether a successful connection has been established. If no, the collector modem hangs up, the “ring count” is reset to zero and the program returns to the point wherein it is waiting to have a “ring count” set by the Modem Ring Interrupt Routine. If a successful connection has been established, the program performs the requested action being asked by the operator of the PC at the other end of the two-way connection. These actions are initiated by the caller using PC configuration software. Actions include setting the collector&#39;s RTC, defining the Upload Call parameters (phone number to call, when to call, etc . . . ) and adding/removing allowed Meter IDs. In addition, the PC configuration software allows the user to download meter readings for any meter and day in the previous two months (or sixty-two days) 
     Upon completing all the requested actions asked by the PC operator, the collector modem hangs up, the “ring count” is reset to zero and the program returns to the point wherein it is waiting to have a “ring count” set by the Modem Ring Interrupt Routine. As with the ring initiation setting, the two-way connection setting can be changed by the programmer/administrator of the system. The “ring count” greater than twenty for establishing a two-way PC connection is used of illustrative purposes, but does represent the value used in the preferred method of operation. It is also noted that the ring initiation value should be less than the two-way PC connection value. 
     Equivalent elements and components can be substituted for the ones set forth above to achieve the same results in the same manner. And, equivalent steps can be employed for the ones set forth above to achieve the same results in the same manner.