Method and apparatus for providing data communication in data monitoring and management systems

[0001] Analyte, e.g., glucose, monitoring systems including continuous and discrete monitoring systems generally include a small, lightweight battery powered and microprocessor controlled system which is configured to detect signals proportional to the corresponding measured analyte levels using an electrometer, and RF signals to transmit the collected data. One aspect of certain glucose monitoring systems include a transcutaneous or subcutaneous analyte sensor configuration which is, for example, partially mounted on the skin of a subject whose glucose level is to be monitored. The sensor cell may use a two or three-electrode (work, reference and counter electrodes) configuration driven by a controlled potential (potentiostat) analog circuit connected through a contact system.

[0002] The compact size of the transmitter unit generally configured to provide water tight seals as its housing does not typically include removable components such as battery covers or additional electrical contacts that may be exposed to the environment or to the patient's skin without the addition of seals and covers. Indeed, other than the electrical contacts of the transmitter unit for coupling the sensor electrodes, the transmitter unit components and its electronic circuitry is generally sealed off from the outside elements to avoid contamination, and potential exposure to water or other fluids that may damage the transmitter unit.

[0003] In view of the foregoing, it would be desirable to have an approach to provide data communication into a sealed electronic device using existing data ports of the electronic device to communicate therewith, in the microprocessor controlled system. More specifically, it would be desirable to have a method and system for accessing the electronics of the transmitter unit (or any other sealed electronic devices) to provide programming instructions and/or otherwise configure the device using the existing data ports of the electronic device.

[0004] In view of the foregoing, in accordance with the various embodiments of the present invention, there is provided a method and apparatus for providing data communication with a sealed and encased electronic device such as a transmitter unit as used in data monitoring systems, using the existing analog electrical contacts of the transmitter units.

[0005] More specifically, in one embodiment of the present invention, there is provided an external interface unit configured to communicate with the transmitter unit electrical contacts configured for coupling to a respective one or more of the analyte sensor electrodes. For example, using an RS 232 interface circuitry, data communication via the transmitter unit electrical contacts may be achieved to program or test the electronic circuitry of the transmitter unit before the transmitter unit is initialized for use by a user in the data monitoring and management system.

[0014] FIG. 1 illustrates a data monitoring and management system such as, for example, an analyte monitoring and management system 100 in accordance with one embodiment of the present invention. In such embodiment, the analyte monitoring and management system 100 includes a sensor unit 101, a transmitter unit 102 coupled to the sensor unit 101, and a receiver unit 104 which is configured to communicate with the transmitter unit 102 via a communication link 103. The receiver unit 104 may be further configured to transmit data to a data processing terminal 105 for evaluating the data received by the receiver unit 104.

[0015] Referring to FIG. 1, also shown is an external serial interface unit 106 operatively coupled to the transmitter unit 102. In one embodiment, the external serial interface unit 106 may be configured to communicate with the transmitter unit 102 via the electrical contacts configured to couple with the sensor unit 101 electrodes. Indeed, as discussed in further detail below, in one embodiment of the present invention, data communication access to the transmitter unit 102 electronics may be achieved via the existing electrical contacts on the transmitter unit 102 such that the integrity of the transmitter unit 102 housing may be maintained.

[0016] More specifically, the external serial interface unit 106 may be configured to establish a one-way data communication to the transmitter unit 102 initially with the factory default settings, and thereafter, perform initial diagnosis, testing, and/or configuration of the transmitter unit 102 to configure the transmitter unit 102 in functional operation with the sensor unit 101, and the receiver unit 104 and/or the data processing terminal 105 in the data monitoring and management system 100. In one embodiment, the external serial interface unit 106 may be configured to establish the one way data communication to the transmitter unit 102 before the sensor unit 101 is coupled to the transmitter unit 102.

[0017] Only one sensor unit 101, transmitter unit 102, communication link 103, receiver unit 104, and data processing terminal 105 are shown in the embodiment of the analyte monitoring and management system 100 illustrated in FIG. 1. However, it will be appreciated by one of ordinary skill in the art that the analyte monitoring and management system 100 may include one or more sensor unit 101, transmitter unit 102, communication link 103, receiver unit 104, and data processing terminal 105, where each receiver unit 104 is uniquely synchronized with a respective transmitter unit 102. Moreover, within the scope of the present invention, the analyte monitoring and management system 100 may be a continuous monitoring system, or a semi-continuous or discrete monitoring system.

[0018] Indeed, analytes that may be monitored include, for example, acetyl choline, amylase, bilirubin, cholesterol, chorionic gonadotropin, creatine kinase (e.g., CK-MB), creatine, DNA, fructosamine, glucose, glutamine, growth hormones, hormones, ketones, lactate, peroxide, prostate-specific antigen, prothrombin, RNA, thyroid stimulating hormone, and troponin. The concentration of drugs, such as, for example, antibiotics (e.g., gentamicin, vancomycin, and the like), digitoxin, digoxin, drugs of abuse, theophylline, and warfarin, may also be monitored.

[0019] In one embodiment of the present invention, the sensor unit 101 is physically positioned on the body of a user whose glucose level is being monitored. The sensor unit 101 may be configured to continuously sample the glucose level of the user and convert the sampled glucose level into a corresponding data signal for transmission by the transmitter unit 102. In one embodiment, the transmitter unit 102 is mounted on the sensor unit 101 so that both devices are positioned on the user's body. The transmitter unit 102 performs data processing such as filtering and encoding on data signals, each of which corresponds to a sampled glucose level of the user, for transmission to the receiver unit 104 via the communication link 103.

[0020] In one embodiment, the analyte monitoring and management system 100 is configured as a one-way RF communication path from the transmitter unit 102 to the receiver unit 104. In such embodiment, the transmitter unit 102 may be configured to transmit the sampled data signals received from the sensor unit 101 without acknowledgement from the receiver unit 104 that the transmitted sampled data signals have been received. For example, the transmitter unit 102 may be configured to transmit the encoded sampled data signals at a fixed rate (e.g., at one minute intervals) after the completion of the initial power on procedure. Likewise, the receiver unit 104 may be configured to detect such transmitted encoded sampled data signals at predetermined time intervals.

[0021] Additionally, in one aspect, the receiver unit 104 may include two sections. The first section is an analog interface section that is configured to communicate with the transmitter unit 102 via the communication link 103. In one embodiment, the analog interface section may include an RF receiver and an antenna for receiving and amplifying the data signals from the transmitter unit 102, which are thereafter, demodulated with a local oscillator and filtered through a band-pass filter. The second section of the receiver unit 104 may include a data processing section which is configured to process the data signals received from the transmitter unit 102 such as by performing data decoding, error detection and correction, data clock generation, and data bit recovery.

[0022] In operation, upon completing the power-on procedure, the receiver unit 104 is configured to detect the presence of the transmitter unit 102 within its range based on, for example, the strength of the detected data signals received from the transmitter unit 102 or a predetermined transmitter identification information. Upon successful synchronization with the corresponding transmitter unit 102, the receiver unit 104 is configured to begin receiving from the transmitter unit 102 data signals corresponding to the user's detected glucose level. More specifically, the receiver unit 104 in one embodiment is configured to perform synchronized time hopping with the corresponding synchronized transmitter unit 102 via the communication link 103 to obtain the user's detected glucose level.

[0023] Referring again to FIG. 1, the data processing terminal 105 may include a personal computer, a portable computer such as a laptop or a handheld device (e.g., personal digital assistants (PDAs)), and the like, each of which may be configured for data communication with the receiver via a wired or a wireless connection. Additionally, the data processing terminal 105 may further be connected to a data network (not shown) for storing, retrieving and updating data corresponding to the detected glucose level of the user.

[0024] Within the scope of the present invention, the data processing terminal 105 may include an infusion device such as an insulin infusion pump, which may be configured to administer insulin to patients, and which is configured to communicate with the receiver unit 104 for receiving, among others, the measured glucose level. Alternatively, the receiver unit 104 may be configured to integrate an infusion device therein so that the receiver unit 104 is configured to administer insulin therapy to patients, for example, for administering and modifying basal profiles, as well as for determining appropriate boluses for administration based on, among others, the detected glucose levels received from the transmitter unit 102.

[0025] FIG. 2 is a block diagram of the transmitter of the data monitoring and detection system shown in FIG. 1 in accordance with one embodiment of the present invention. Referring to the Figure, the transmitter unit 102 in one embodiment includes an analog interface 201 configured to communicate with the sensor unit 101 (FIG. 1), a user input 202, and a temperature detection section 203, each of which is operatively coupled to a transmitter processor 204 such as a central processing unit (CPU).

[0026] As can be seen from FIG. 2, there are provided four contacts, three of which are electrodes—work electrode (W) 210, guard contact (G) 211, reference electrode (R) 212, and counter electrode (C) 213, each operatively coupled to the analog interface 201 of the transmitter unit 102 for connection to the sensor unit 201 (FIG. 1). In one embodiment, each of the work electrode (W) 210, guard contact (G) 211, reference electrode (R) 212, and counter electrode (C) 213 may be made using a conductive material that is either printed or etched, for example, such as carbon which may be printed, or metal foil (e.g., gold) which may be etched.

[0027] In one embodiment, the external serial interface unit 106 (FIG. 1) may be operatively coupled to the transmitter unit 102 electrical contacts for the guard contact 211 and the counter electrode 213, respectively, to establish data communication with the electronics of the transmitter unit 102, and further, to perform the desired configuration and/or diagnosis procedures on the transmitter unit 102 from the manufacturer factory settings. In this manner, as will be discussed in further detail below, the external serial interface unit 106 in one embodiment of the present invention may be configured to communicate with the processor 204 of the transmitter unit 102 via the serial communication section 205, and thereafter, transmit the resulting data and/or information to, for example, the receiver unit 104 via the RF transmitter 206 of the transmitter unit 102.

[0028] Further shown in FIG. 2 are a transmitter serial communication section 205 and an RF transmitter 206, each of which is also operatively coupled to the transmitter processor 204. Moreover, a power supply 207 such as a battery, including a rechargeable battery, is also provided in the transmitter unit 102 to provide the necessary power for the transmitter unit 102 where the guard contact (G) 211 and the counter electrode (C) 213 are configured to couple to the power supply 207 through ESD clamp diodes (in the analog interface 201). Additionally, as can be seen from the Figure, clock 208 is provided to, among others, supply real time information to the transmitter processor 204.

[0029] In one embodiment, the power supply 207 may be configured to be recharged via a select pair of the plurality of electrodes 210-213 such as the guard contact 211 and counter electrode 213, when the transmitter unit 102 is not mounted to a patient and configured for periodic transmission of measured data to the receiver unit 103. As further discussed below, the power supply 207 may be coupled or docked to a battery charging station or unit during the recharge process, where the power supply 207 is recharged and, thereafter, when the transmitter unit 102 is mounted to the patient and coupled to the sensor unit 101, the power supply 207 may be configured to provide the necessary power to reliably operate the transmitter unit 102.

[0030] Referring back to the Figures, in one embodiment, a unidirectional input path is established from the sensor unit 101 (FIG. 1) and/or manufacturing and testing equipment via the external serial interface unit 106 to the analog interface 201 of the transmitter unit 102, while a unidirectional output is established from the output of the RF transmitter 206 of the transmitter unit 102 for transmission to the receiver unit 104. In this manner, a data path is shown in FIG. 2 between the aforementioned unidirectional input and output via a dedicated link 209 from the analog interface 201 to serial communication section 205, thereafter to the processor 204, and then to the RF transmitter 206.

[0031] As such, in one embodiment, via the data path described above, the transmitter unit 102 is configured to transmit to the receiver unit 104 (FIG. 1), via the communication link 103 (FIG. 1), processed and encoded data signals received from the sensor unit 101 (FIG. 1). Additionally, the unidirectional communication data path between the analog interface 201 and the RF transmitter 206 discussed above allows for the configuration of the transmitter unit 102 for operation upon completion of the manufacturing process as well as for direct communication for diagnostic and testing purposes.

[0032] As discussed above, the transmitter processor 204 may be configured to transmit control signals to the various sections of the transmitter unit 102 during the operation of the transmitter unit 102. In one embodiment, the transmitter processor 204 also includes a memory (not shown) for storing data such as the identification information for the transmitter unit 102, as well as the data signals received from the sensor unit 101. The stored information may be retrieved and processed for transmission to the receiver unit 104 under the control of the transmitter processor 204. Furthermore, the power supply 207 may include a commercially available non-rechargeable battery or a proprietary or commercially available rechargeable battery.

[0033] The transmitter unit 102 is also configured such that the power supply section 207 does not significantly affect the battery life after having been stored for 18 months in a low-power (non-operating) mode. In one embodiment, this may be achieved by the transmitter processor 204 operating in low power modes in the non-operating state, for example, drawing no more than approximately 1 μA of current. Indeed, in one embodiment, the final step during the manufacturing process of the transmitter unit 102 may place the transmitter unit 102 in the lower power, non-operating state (i.e., post-manufacture sleep mode). In this manner, the shelf life of the transmitter unit 102 may be significantly improved.

[0034] Referring yet again to FIG. 2, the temperature detection section 203 of the transmitter unit 102 is configured to monitor the temperature of the skin near the sensor insertion site. The temperature reading is used to adjust the glucose readings obtained from the analog interface 201. The RF transmitter 206 of the transmitter unit 102 may be configured for operation in the frequency band of 315 MHz to 322 MHz, for example, in the United States. Further, in one embodiment, the RF transmitter 206 is configured to modulate the carrier frequency by performing Frequency Shift Keying and Manchester encoding. In one embodiment, the data transmission rate is 19,200 symbols per second, with a minimum transmission range for communication with the receiver unit 104.

[0035] Additional detailed description of the continuous glucose monitoring system, its various components including the functional descriptions of the transmitter are provided in U.S. Pat. No. 6,175,752 issued Jan. 16, 2001 entitled “Analyte Monitoring Device and Methods of Use”, and in application Ser. No. 10/745,878 filed Dec. 26, 2003 entitled “Continuous Glucose Monitoring System and Methods of Use”, each assigned to the Assignee of the present application.

[0036] FIG. 3 illustrates the front end section of the analog interface of the transmitter in accordance with one embodiment of the present invention. Referring to the Figure, the front end section of the analog interface 201 includes a current to voltage circuit 301 which is configured to operatively couple to the work electrode 210 and the guard contact 211, and a counter-reference servo circuit 302 which is configured to operatively couple to the reference electrode 212 and the counter electrode 213.

[0037] FIGS. 4A-4C respectively show detailed illustrations of the current to voltage circuit, the counter-reference servo circuit of the analog interface, and the comparator circuitry operatively coupled to the current to voltage circuit and the counter-reference servo circuit shown in FIG. 3 in accordance with one embodiment of the present invention. Referring to FIG. 4A, the current to voltage circuit 301 (FIG. 3) in one embodiment includes an operational amplifier 402 having a non-inverting input terminal 405, and an inverting input terminal 404. Also shown in the Figure is a resistor 401 operatively coupled to the inverting input terminal 404 of the operational amplifier 402, and an output terminal 406.

[0038] Referring again to FIG. 4A, the work electrode 210 is operatively coupled to the inverting input terminal 404 of the operational amplifier 402, while the guard contact 211 is operatively coupled to the non-inverting input terminal 405 of the operational amplifier 402. It can be further seen that the work voltage source Vw is provided to the non-inverting terminal 405 of the operational amplifier 402. In this manner, in accordance with one embodiment of the present invention, a separate contact, the guard contact 211 is operatively coupled to the analog interface 201 (FIG. 2) of the transmitter unit 102 (FIG. 2). The guard contact 211 is provided at a substantially equipotential to the work electrode 210 such that any current leakage path to the work electrode 210 (from either the reference electrode 212 or the counter electrode 213, for example) is protected by the guard contact 211 by maintaining the guard contact 211 at substantially the same potential as the work electrode 210.

[0039] Moreover, a resistor 412 may be provided between the guard contact 211 electrical contact (at the transmitter unit 102 analog interface unit 201) and the non-inverting input terminal 405 of the operational amplifier 402 of the current to voltage circuit 301 (FIG. 3). As will be discussed in further detail below, the resistor 412 in conjunction with a resistor coupled between the counter electrode 213 and the output terminal 410 of the operational amplifier 407 (FIG. 4B), are configured to allow serial data input on the counter electrode 213 electrical contact at the transmitter unit 102 analog interface unit 201, such that the output signal at the output terminal 410 of the operational amplifier 407 for the counter-reference servo unit 302 (FIG. 3), may be overdriven without potentially damaging the operational amplifier 407.

[0040] Referring now to FIG. 4B, the counter-reference servo unit 302 in accordance with one embodiment includes an operational amplifier 407 having an inverting input terminal 408 and a non-inverting input terminal 409, as well as an output terminal 410. In one embodiment, the reference electrode 212 is operatively coupled to the inverting input terminal 408, while the counter electrode 213 is operatively coupled to the output terminal 410 of the operational amplifier 407 in the counter-reference servo unit 302. It can also be seen from FIG. 4B that a reference voltage source Vr is provided to the non-inverting input terminal 409 of the operational amplifier 407 in the counter-reference servo unit 302.

[0041] Referring back to FIGS. 3 and 4A-4B, in accordance with one embodiment of the present invention, the current to voltage circuit 301 and the counter-reference servo unit 302 are operatively coupled to the remaining sections of the analog interface 201 of the transmitter unit 102, and configured to convert the detected glucose level at the sensor unit 101 (FIG. 1) into an analog signal for further processing in the transmitter unit 102. It should also be noted that, in the manner described, the Poise voltage (for example, at a value of 40 mV) may be determined based on the difference between the voltage signal level of the work voltage source Vw at the non-inverting input terminal 405 of the operational amplifier 402 in the current to voltage circuit 301, and the voltage signal level of the reference voltage source Vr at the non-inverting input terminal 409 of the operational amplifier 407 in the counter-reference servo unit 302.

[0042] Referring back to FIG. 4B and as discussed above, the resistor 411 is provided between the electrical contact for the counter electrode 213 at the analog interface unit 201 of the transmitter unit 102 and the output terminal 410 of the operational amplifier 407 of the counter-reference servo circuit 302. In this manner, in one embodiment of the present invention, when the external serial interface unit 106 (FIG. 1) is operatively coupled to the electrical contacts of the transmitter unit 102 for the counter electrode 213 and the guard contact 211 of the sensor unit 101 (FIG. 1), the serial data input signals from the external serial interface unit 106 may not adversely effect the operational amplifier 407 of the counter-reference servo circuit 302.

[0043] Referring now to FIG. 4C, there is provided a comparator 420 having a non-inverting input terminal 421, an inverting input terminal 422, and an output terminal 423. In one embodiment, the non-inverting input terminal 421 of the comparator 420 is configured to couple to the electrical contact for the counter electrode 213 of the transmitter unit 102 analog interface unit 201. Moreover, the inverting input terminal 422 of the comparator 420 is configured to operatively couple to the electrical contact for the guard contact 211, of the transmitter unit 102 analog interface unit 201. Finally, the output terminal 423 of the comparator 420 is configured to couple to the serial communication section 205 (FIG. 2) of the transmitter unit 102.

[0044] In one embodiment, the comparator 420 may be configured to be polarity programmable to match that of the serial communication section 205 (FIG. 2) of the transmitter unit 102.

[0045] FIG. 5 illustrates an external serial interface unit for use in the data monitoring and management system in one embodiment of the present invention. Referring to FIG. 5, the external serial interface unit 500 in accordance with one embodiment includes an RS-232 data port 501 operatively coupled to an RS-232 conversion unit 502. In one embodiment, the RS-232 data port 501 may include male or female pins or sockets. Furthermore, the pin connections 506, 507 between the RS-232 data port 501 and the RS-232 conversion unit 502 may be pin #2 or #3, and the ground (pin #5) at the RS-232 data port, respectively depending upon a straight through or null-modem data transmit. The type of connectors (pins or sockets) and polarity (straight through or mull modem) may be selected using commercially available cables.

[0046] Referring back to FIG. 5, it can be seen that the RS-232 conversion unit is operatively coupled to the transmitter unit 102 analog interface unit 201 electrical contact of the counter electrode 213 via connection 503, and a logic inverter 505 is provided to drive the transmitter unit 102 analog interface unit 201 electrical contact for the guard contact 211 to establish a differential drive for signaling.

[0047] In other words, the connection 503 of the RS 232 conversion unit (FIG. 5) is operatively coupled to the non-inverting input terminal 421 of the comparator 420 (FIG. 4C), while the connection 504 of the RS 232 conversion unit (FIG. 5) is operatively coupled to the inverting input terminal 422 of the comparator 420 (FIG. 4C). This configuration allows for a differential drive signal into the transmitter unit 102 in the absence of a ground reference. The differential drive signal may be then recovered using the comparator 420 shown in FIG. 4C.

[0048] FIGS. 6A-6B are schematics of the serial data communication in accordance with various embodiments of the present invention. Referring to FIG. 6A, it can be seen that the external serial interface unit 106 (FIG. 1) is coupled to the electrical contacts for the guard contact 211 and the counter electrode 213 at the analog interface unit 201 of the transmitter unit 102. In turn, the electrical contacts for the guard contact 211 and the counter electrode 213 of the analog interface unit 201 are operatively coupled to the non-inverting input terminal 412 and the inverting input terminal 422, respectively of the comparator 420.

[0049] Referring to FIG. 6B, instead of using the electrical contact at the analog interface unit 201 of the transmitter unit for the guard contact 211, the electrical contact of the analog interface unit 201 of the transmitter unit 102 for the work electrode 210 is operatively coupled to the external serial interface unit 106 in conjunction with the electrical contact of the analog interface unit 201 of the transmitter unit 102 for the counter electrode 213. Moreover, it can be seen from FIG. 6B that the comparator 420 is provided to the transmitter unit 102 and whose non-inverting input terminal 421 and the inverting input terminal 422 are operatively coupled to the electrical contacts of the transmitter unit 102 for the work electrode 210 and the counter electrode 213.

[0050] FIG. 7 illustrates a block diagram of the data flow in the data communication from the external serial interface unit and the transmitter unit in accordance with one embodiment of the present invention. Referring to FIG. 7, it can be seen that the drive circuit 500 which in one embodiment includes the external serial interface unit 106 is configured to operatively couple to the existing data ports such as the electrical contacts for coupling to the sensor unit 101 electrodes. The data signals from the drive circuit 500 are then provided to the processor 204 of the transmitter unit 102 via the serial communication section 205, and thereafter, the resulting data or information may be provided to the RF transmitter 206 to be transmit to, for example, the receiver unit 104.

[0051] In this manner, within the scope of the present invention, there is provide a method and system for communicating with an electronic device such as a transmitter unit of a data monitoring and management system provided in a substantially sealed housing for accessing the electronics of the internal circuitry of the electronic device during manufacturing, to perform for example, failure analysis, programming, calibration, boot loading, and/or for device design and testing procedures such as debug commands which may be provided to the transmitter unit in various modes to perform tests on various features.

[0052] Indeed, by providing an alternate manner in which to use existing data ports or contacts to communicate with the electronic device, substantial cost savings, complexity in design and constraint from size limitations, may be achieved. Indeed, in the case of a transmitter unit for use in the data monitoring and management system, it is possible to provide access to the transmitter unit electronics via the existing data ports or contacts, in lieu of designing the transmitter unit to include data receiver capability (for example, by providing a transceiver unit).

[0053] Accordingly, a data monitoring system in one embodiment of the present invention includes a transmitter unit including a data port, and an interface unit operatively coupled to the transmitter unit, the interface unit configured to establish a uni-directional data communication with the transmitter unit via the data port.

[0054] The transmitter unit may include a housing that is substantially water tight.

[0055] Furthermore, the transmitter unit may be configured to transmit data over a wireless data network, which includes, in one embodiment, an RF data transmission network. Indeed, the transmitter unit may include an RF transmitter.

[0056] The transmitter unit data port in one embodiment may include one or more electrical contacts configured for receiving one or more signals corresponding to an analyte level.

[0057] The system may further include a sensor unit configured to couple the data port of the transmitter unit, where the sensor unit may include an analyte sensor (such as a glucose sensor).

[0058] The sensor unit in one embodiment may be configured detect an analyte level of a patient.

[0059] A data monitoring system in another embodiment includes a transmitter unit including an input port and an output port, an interface unit operatively coupled to the transmitter unit input port, the interface unit configured to transmit signals to the transmitter unit via the input port, a receiver unit operatively coupled to the transmitter unit output port, the receiver unit configured to receive data from the transmitter unit over a data network.

[0060] The output port of the transmitter unit may include a wireless data port (such as an RF transmission data port).

[0061] In one embodiment, the interface unit may be configured to perform one or more of a transmitter unit diagnosis procedure, programming procedure, fault detection procedure, or a configuration procedure.

[0062] The interface unit may include an RS-232 interface circuit.

[0063] A method in yet another embodiment includes the steps of operatively coupling an interface unit to a data port of a transmitter unit, transmitting signals to the transmitter unit via the data port in a uni-directional path.

[0064] The method may further include the step of wirelessly transmitting data from the transmitter unit to a receiver unit, including for example, transmitting data over an RF data transmission path.

[0065] The step of transmitting signals to the transmitter unit may include the step of performing a predetermined procedure on the transmitter unit, where the predetermined procedure may include one or more of a transmitter unit diagnosis procedure, a transmitter unit programming procedure, a transmitter unit fault detection procedure, or a transmitter unit configuration procedure.

[0066] Various other modifications and alterations in the structure and method of operation of this invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. It is intended that the following claims define the scope of the present invention and that structures and methods within the scope of these claims and their equivalents be covered thereby.