Contactless communication system.

Background of the Invention

Field of the Invention

This invention concerns a contactless connection system and method for communicating digital information between a portable data-gathering device and a data-using device. In a preferred embodiment, it employs the system and method to communicate from a data-gathering medication event monitor to a reader-display computer/terminal. The medication event monitor is used to gather data regarding a patient's compliance with a medication regimen and/or patient-included or entered data concerning the patient's condition or compliance, and these data are transferred to a device where they can be read or displayed pr otherwise used. Contactless connection can also be used to power up the portable device or to send other signals between the devices.

Background Information

There is an increasing understanding throughout the health care community that information concerning patient compliance with medication regimens is important. Understanding whether or not medications have been timely taken facilitates correct diagnosis of disease states. It also facilitates a correct understanding of drug effectiveness.

A number of devices have been proposed to keep track of a patient's drug dose taking patterns. See, for example:    United States patent no. 4,725,997, issued February 16, 1988 to John Urquhart et al.;    United States patent no. 4,695,954, issued September 22, 1987 to Robert J. Rose et al.;    United States patent no. 4,674,652, issued June 23, 1987 to Edward M. Aten et al.;    Unites States patent no. 4,662,537, issued May 5, 1987 to James L. Wolf et al.; and    United States patent no. 4,616,316, issued October 7, 1986 to John A. Hanpeter et al., for representative disclosures of devices which collect drug dispensing information.

In these representative devices of the art, it is common to have a clock generating a real time or elapsed time signal, a switch of some sort to signal when a dose is taken, and a memory for electronically recording the time at which each dosing signal is received. In these devices, this mechanism can often be associated with the container for the medication itself. This offers advantages of portability and ease of patient use.

The fact that the record of drug dose compliance is stored in the memory of a patient-portable device means that there must be a way to debrief the device and download the device memory. This makes the information contained in the memory accessible to the health care professional overseeing the patient's progress or to the patient him- or herself. This need for access means that there must be a data port of some sort provided in the medication monitor. This data port is used to access information contained in the memory of the patient-portable device and also can be used to feed information into the device. Examples of information which might be fed into the device include a desired dose regimen. The patient-portable device could use this information to trigger alarms at suitable time intervals. The information could also be general instructions or the like for the device to display to the patient at dosing times. An explanation of these types of displays is provided in above-referenced United States patent no. 4,725,997, which is incorporated herein by reference.

Heretofore, this data port in the medication event monitoring unit has been in the form of a multi-terminal plug body. In the field, however, a plug body connection can have shortcomings. For one, the plug body can short out if wet, which can occur in bathroom and kitchen settings. For another, it can become clogged with debris, especially with pill containers which are often carried in pockets or purses. In addition, since these devices are typically quite small and the plug bodies miniaturized, there is a real opportunity for misuse and damage during the connecting and disconnecting with the plug body. A need has been identified for a device and method for quickly and accurately providing a data transmission port into and out of portable data-gathering devices. This need arises in many applications. These can include transmitting digital information into and out of time clocks, into and out of digital recorders, and the like. An improved port into portable data-gathering devices might also be advantageous for feeding power into the device.

Brief Description of the Invention

The present invention relates to the use of contactless communication between a portable data-gathering device and a data-processing/using device. The contactless coupling of this system can be used to communicate data from a portable data-gathering device to a data-processing/using device. It also can be used to transmit other information between the devices and to feed power to the portable device.

The contactless communication system most commonly employs inductive coupling between the two devices but also may employ a pulsed or modulated low power radio-frequency signal, or an optical or a sonic or ultra-sonic signal to communicate data between the data-gathering unit and the data-receiving unit. In use, the two devices must be brought into operative proximity of each other to effect the coupling. In the case of inductive coupling this is a matter of a few inches or less and, in the case of other modes of communication, typically a few hundred feet or less. The data processing/using unit may include the data-receiving section as an integral part or it may be coupled to a separated data-receiving unit directly or via a network.

In a preferred embodiment, the data-coupling system employs a electromagnetic inductor in the portable data-gathering unit. This inductor converts digital data gathered and stored in the data-gathering unit into a series of electromagnetic pulses. These electromagnetic pulses are detected by a second inductor in the processing unit and converted into a series of electrical pulses. The processing unit then processes the electrical signals so received back into digital data which are stored or displayed or otherwise employed.

In a preferred embodiment, these devices are used in the monitoring, storing and reporting of medication events with the portable data-gathering unit being a medication event monitor and the data processing/using unit being a display or terminal such as for use by health care professionals interested in the patient's medication regimen compliance.

In an alternative embodiment, the data-processing/using unit is equipped to send signals to the data-gathering unit over the same contactless (e. g. inductor/inductor) link. These signals communicated from the data-processing/using unit to the data-gathering unit may include patient data and program information. Patient data can be used by the data-gathering unit internally to issue warning signals or may be made available to the data-processing/using unit at a later time. This allows the data-gathering unit to be programmed or the like so as to modify its behavior in the medication event monitoring process. Having patient data available within the data-gathering device for readout by the data-processing/using unit permits the data-gathering device to identify its patient when it is communicating with a variety of data-using devices. This makes the use of a particular data-gathering unit independent of a particular data processing/using unit.

Thus, in one aspect, this invention provides a contactless data communication system. The system includes a portable data-gathering unit and a data-processing/using unit. The portable data-gathering unit includes a digital data generator and a memory for storing the digital data. The data-gathering unit is also equipped to retrieve the digital data from its memory and feed it as a series of electrical pulses to a first inductor. This inductor converts the electrical pulses into electromagnetic pulses. The data-receiving unit includes a second inductor. The two inductors are brought into operative proximity with one another by positioning the data-gathering unit in a predefined position relative to the data-receiving unit. The inductor coil of the data-receiving unit senses the electromagnetic pulses generated by the inductor of the data-gathering unit and converts the received electromagnetic pulses into a series of received electrical pulses. These received electrical impulses are then amplified and converted into digital data. The digital data so formed can be used in any manner. For example, the digital data can be stored for later review, can be displayed for immediate review, can be printed, or can be transmitted to another data-receiving using device, such as some computing means.

In another aspect, this invention provides a contactless method of data communication between a portable data-gathering unit and a data-receiving station. In this method, the data is gathered and stored as digital data in a memory in the portable data-gathering unit. At a later time, the data is called up from the memory and turned into a series of electrical pulses. This series of electrical pulses is fed to an inductor coil located in the data-gathering unit at a location most suitable for transmitting the data to a receiving data-receiving unit. The digital data stream is converted by the inductor coil into a series of electromagnetic pulses. These electromagnetic pulses are received in an inductor coil located in the receiving data-receiving unit at a location most suitable for receiving such electromagnetic signals. In this method, the pulses picked up by the inductor coil of the data-receiving unit are then converted into analog electrical pulses which are amplified and converted into digital pulses. These digital pulses represent digital data which can be thereafter stored or displayed or printed or the like.

In another aspect, the device and method of this invention can be made to operate bidirectionally by equipping the data-receiving/processing unit with a circuit for feeding a series of electrical pulses to the second inductor and thereby generating a second series of electromagnetic pulses in the second inductor which can be sensed by the inductor coil of the data-gathering unit. In this case, the data-gathering unit is equipped with a suitable circuit to convert the series of electrical pulses generated by its inductor into digital data. This digital data is then used and/or stored in the data-gathering unit. This embodiment finds application when the data-gathering unit also provides some forms of information to the patient. For example, it may trigger an alarm or other alerting device to tell the patient when to take drug doses or it may trigger a display or the like to provide other information to the patient.

In still another preferred embodiment a third unit is employed to generate an alarm to the user. This third unit, the alarm unit, is equipped to communicate with the data-gathering unit or the data-receiving unit. Furthermore, this alarm unit may be combined with a pager-receiver for receiving information via a pager system.

In another aspect of the invention a contactless connection, and particularly an inductor/inductor coupling can be used as a power channel for powering-up the portable data collector. This configuration can lead to very advantageous easy recharging of the electrical power storage section of the data-collection device and permit this device to have a small power storage capacity.

Brief Description of the Drawings

This invention will be further described with reference being made to the accompanying drawings in which <ul id="ul0001" list-style="none"><li>FIG. 1 is a schematic block diagram of one form of the data communications system of this invention;</li><li>FIG. 2 is a schematic block diagram of a second, dual-direction, data communication system in accordance with the present invention in which the data-gathering device is embodied as a medication container set up to monitor a patient's compliance with a medication regimen.</li><li>FIG. 3 is a schematic circuit diagram for an embodiment of the data-receiving device/data-gathering device interface of the system; and</li><li>FIG. 4 is an illustration of the two types of information packets used in the communication system.</li><li>FIG. 5 is a flowchart of the data-receiving unit's transmission activities illustrating the initiation of information transfer between the data-receiving device and the data-gathering device.</li><li>FIG. 6 is a transmission receive flowchart illustrating a data-gathering unit monitor packet transmission protocol.</li><li>FIG. 7 is an illustration of an electro-optical interface between a data-gathering device and a data-receiving device.</li></ul>

Description of Preferred Embodiments

FIG. 1 is an illustration of a first preferred embodiment <b>10</b> of the data communications system of the present invention. System <b>10</b> includes medication event monitoring data-gathering unit <b>20</b> and data-receiving unit <b>60</b>. Data-gathering unit <b>20</b> includes a microprocessor <b>102</b> coupled to clock <b>104</b> and bidirectionally connected to memory <b>106</b> such that information can be passed into the memory <b>106</b> from microprocessor <b>102</b> and read from the memory <b>106</b> by microprocessor <b>102</b>. Microprocessor <b>102</b> is also connected to event detector <b>108</b>, monitors event detector <b>108</b> and performs the appropriate operations on event detection signals generated by detector <b>108</b> so that data based on these signals can be generated and stored in memory <b>106</b>. The interface between event detector <b>108</b> and microprocessor <b>102</b> may be interrupt and/or inquiry based.

At least one type of medication event will cause collection of data by data-gathering unit <b>20</b>. One type of event could be directly related to the medication event - for example the opening of a medicament container as an indication that a dose of medicament has been taken. In this case, event detector <b>108</b> can be a switch or the like device which can send a signal based on detecting an event. Other events which may be noted may be patient-initiated to indicate timewise compliance with some aspect of a dosing regimen. Still other events may allow monitoring the amount of medication taken by the patient or may indicate the occurrence of a certain condition for which the patient was asked to activate an event switch, that is, to manually activate a data generation signal. Any of these events can be detected by suitable means <b>108</b> with the detection signal monitored by microprocessor <b>102</b>. Each time activator or event switch <b>108</b> is triggered, microprocessor <b>102</b> starts gathering digital data related to the event, for example the time that the event took place as determined by clock <b>104</b>, and stores these data in memory <b>106</b>.

Microprocessor <b>102</b> also is connected to event switch <b>110</b> and to inductor <b>112</b>. Whenever event switch <b>110</b> detects a second type event, for example a manual switch activation or a suitable signal, it signals microprocessor <b>102</b> to change its function to reading gathered data from memory <b>106</b> and feeding the data as a stream of digital electrical pulses to inductor <b>112</b>. The stream of pulses may be the digital data stream itself from memory <b>102</b> or it may be a signal suitably altered in power so as to effectively drive inductor <b>112</b>. Inductor <b>112</b> converts the stream of electrical pulses into a corresponding series of electromagnetic signals.

When the data-gathering unit <b>20</b> and the data-receiving/using unit <b>60</b> are brought into operative proximity with one another, unit <b>60</b> can sense the electromagnetic signals generated by inductor <b>112</b>. Inductor <b>112</b> is located close to an exterior wall <b>116</b> of housing <b>114</b>. If inductor <b>112</b> is in close proximity to inductor <b>134</b> of data-receiving unit <b>60</b> the electromagnetic signals generated by inductor <b>112</b> are sensed by inductor <b>134</b>, converted into a series of electrical pulses which are fed to microprocessor <b>136</b> and ultimately to data use device <b>138</b>. Device <b>138</b> may be a display, a printer, a memory, a device performing data analysis operations, a data-manipulating device, a data transfer device for communicating the received data to other devices, or any other device for handling the received data. Inductor <b>134</b> is located close to wall <b>130</b> of housing <b>132</b> of data-receiving unit <b>60</b>.

The system just described is a one-way system. That is, information is gathered in unit <b>20</b> and fed to unit <b>60</b> where it is displayed or otherwise used.

In FIG. 2 a communication system <b>12</b> is shown. System <b>12</b> is a two-way system made up of data-gathering unit <b>22</b> and data-receiving unit <b>62</b>. Data-gathering unit <b>22</b> is configured as a medication container <b>213</b> with cap <b>214</b>. Cap <b>214</b> has a top surface comprising wall <b>216</b>. Threads <b>218</b> and <b>220</b> hold cap <b>216</b> onto container <b>213</b>.

In FIG. 2 container <b>213</b> is shown in inverted orientation. The data-gathering arrangement of data-gathering unit <b>22</b> includes microprocessor <b>202</b>, clock <b>204</b> and memory <b>206</b>. Event switch <b>208</b> is a microswitch which is located so as to be tripped whenever cap <b>214</b> is removed from container <b>213</b>. A signal from switch <b>208</b> is fed to microprocessor <b>202</b> to be correlated with a time of day or elapsed time value from clock <b>204</b> and fed as digital data to memory <b>206</b>. This gives a record in memory <b>206</b> of the time that a drug dose was requested by a patient by way of removing the cap of the drug container.

At preset intervals, or on demand such as by an event signal from switch <b>215</b>, or on demand by a signal from data receiving unit <b>62</b>, as will be disclosed below, microprocessor <b>202</b> reads data from memory <b>206</b> and passes the data through data switch <b>211</b> to inductor <b>212</b>. The data which are fed to inductor <b>212</b> as a series of electrical pulses are converted into a series of electromagnetic pulses. These may be sensed by a corresponding inductor <b>234</b> in data-receiving unit <b>62</b> in housing <b>230</b>, which in turn generates a series of electrical pulses. These received pulses pass through "receive/send" switch <b>235</b> into microprocessor <b>236</b> and thereafter into a data use device, i.e., printer, memory, display, a processor for analysis or calculation processes etc., <b>238</b>. Switch <b>235</b> is a two state switch and connects inductor <b>234</b> into a circuit for receiving pulses from inductor <b>212</b> or for sending pulses to inductor <b>212</b>. Data-gathering unit <b>62</b> contains a similar "send/receive" switch <b>211</b> for switching the function of its inductor <b>212</b>.

Data-gathering unit <b>22</b> can additionally contain other function units such as, for example, display or alarm device <b>250</b> linked to microprocessor <b>202</b>. Device <b>250</b> could be an alarm designed to give off alerting signals when a dose of medication should be taken. Device <b>250</b> could be a display or enunciator designed to provide information to the patient about the dosage regimen. These pieces of information to be displayed or otherwise employed could, in one embodiment, be stored over long time periods in memory <b>206</b> or any other memory in unit <b>22</b>. This information could be periodically recalled from memory 206 by the action of microprocessor <b>202</b> and clock <b>204</b>.

This information could also be recalled from memory <b>206</b> based on digital instructions sent to unit <b>22</b> by the two way communication channel to unit <b>62</b>. It could also be variable stored information which could be altered and used following digital instructions provided by data-receiving unit <b>62</b>. It also could be information based on digital signals communicated to unit <b>22</b> by unit <b>62</b>. In this two-way communication link, the information or signals are fed via switch <b>235</b>, inductor <b>234</b> to inductor <b>212</b> and thence to microprocessor <b>202</b> and to memory <b>206</b> of data-gathering unit <b>22</b>. In this embodiment, data use unit <b>62</b> would include a data-providing device <b>252</b> such as a keyboard, a memory or other information source which would feed information to microprocessor <b>236</b>, then to switch <b>235</b>, which would then be in the send position and onto inductor <b>234</b> for transmission.

Instead of using a switch <b>215</b> other means can be employed to initiate processor <b>202</b> to transmit data to the data-receiving unit <b>62</b> in a bi-directional system. Such means may include some qualifying means to allow activation of processor <b>202</b> only if data-gathering unit 22 is operatively proximate to data-receiving unit <b>62</b>.

In the preferred application just described this invention is employed in a medical event monitoring system. The data-gathering function would be carried out in a medication container, either in the cap as shown or elsewhere in the body of the device. In FIG. 2 data-gathering unit <b>22</b> is represented by a pill container <b>213</b> with a screw top <b>214</b>. Other types of medication containers can be adapted for collecting data regarding the use of medication in a similar fashion. A container for liquid medication may include a drop counter or a medication pump which activate a switch generating a signal when and how much medication was dispensed. The data gathering unit may be an inhaler, a pill dispenser with pill ejector, a blisterpack for pills, or a unifunction device for displaying information or recording medical events such as side effects, clinical symptoms, clinical occurrences etc.

In this embodiment, when the patient receives a container of medication, the data-gathering device would be activated and would, during the dosage regimen, gather information about the patient's compliance with the desired dose regimen. At later times, such as when visiting the physician or when having the medication container refilled, the medication container would be placed in a reader such that its inductor coil <b>212</b> would be moved adjacent to the corresponding coil <b>234</b> in the data-receiving unit. A data report signal would be furnished by the data-receiving unit to the microprocessor of the data-gathering unit and the health care professional would then obtain the information collected in the memory of the data-gathering unit. Depending on the system, this could result in an erasure of the data in the memory or, alternatively, if adequate memory capacity was available, the information could remain in the memory in the container until a later removal. The information thus gathered in the data-receiving device <b>62</b> could be printed out so that compliance could be checked, it could be displayed for the same purpose, or the like. In addition, when the device is available to the health care professional, it would be possible to reprogram the data-gathering portion by using the two-way communication. In this manner, a new regimen could be inserted which could be used to control an alerting or enunciating device if present in the data-gathering unit. In addition, other instructions could be loaded into memory <b>206</b> and could later be furnished to the patient.

The application of this invention is not limited to the preferred area of medication event and compliance monitoring. In theory, any system in which digital data is gathered in one location by a portable device and later communicated to a separate data-using or processing device could benefit from the application of this invention. Such systems could include, for example, portable electronic notebooks for inspectors or "meter-readers" or security officers, or even communication between portable laptop or "notebook" computers and a fixed data-processing center.

An example of suitable electrical circuitry to carry out the invention is provided in FIG. 3. FIG. 3 is a schematic block diagram of a communication interface circuit which can be used for establishing bidirectional communication between a data-gathering unit <b>301</b> and a data-receiving unit <b>303</b> of the present invention. This arrangement includes inductor coil <b>300</b> of data-gathering unit <b>301</b> and inductor coil <b>322</b> of data-receiving unit <b>303</b>. When communicating data from data-gathering unit <b>301</b> to data-receiving unit <b>303</b> inductor <b>300</b> generates a electro-magnetic field which is sensed by inductor <b>322</b> at an operatively proximate distance of from about 0 to about 0.5 inches. When communicating data from data-receiving unit <b>303</b> to data-gathering unit <b>301</b> inductor <b>322</b> generates a electro-magnetic field which is sensed by inductor <b>300</b> at similar distances. To reduce power requirements in the data-gathering device <b>301</b> a dual mode of operation is employed: a communication mode and a wait and data-gathering mode. All communication operations are initiated by the data-receiving unit <b>303</b>. The first transmission from <b>303</b> includes activation of the sending inductor <b>322</b> for a period of 4 command bit cells to allow the receive circuit of the data-gathering device <b>301</b> to settle. After transmitting the last packet the sending inductor <b>322</b> remains activated for 3 command bit times, which is interpreted by the monitoring device <b>301</b> as an end-of-packet signal.

The signal generated by inductor <b>322</b> of data-receiving unit <b>303</b> when sensing a change in a electromagnetic field is fed to differential amplifier <b>304</b>. The AC output signal of amplifier <b>304</b> is fed to amplifier <b>307</b>. The AC component of the output signal of amplifier <b>307</b> is fed to dynamic threshold circuit <b>309</b> to provide a reference voltage <b>312</b>. Reference voltage <b>312</b> fluctuates with the amplitude of the received and amplified signal and changes the sensitivity of amplifier <b>313</b> in accordance with the received signal. The output signal of amplifier <b>313</b> provides the proper binary logic level signal <b>315</b>. Data signal <b>315</b> is sampled on the negative edge by the microprocessor of the data-receiving unit <b>303</b>. This arrangement of amplifiers thus converts a stream of electro-magnetic pulses induced into the inductor <b>322</b> into a stream of data pulses.

When transmitting information from data-gathering unit <b>301</b> to data-receiving unit <b>303</b>, inductor <b>300</b> is driven with current pulses controlled by the microprocessor of data gathering unit <b>301</b>. In the receiver circuit of the data-receiving unit <b>303</b> signal COM-RCV-Enable* on line <b>311</b> connects inductor coil <b>322</b> via switched transmit squelch circuit <b>323</b> to receive amplifier <b>304</b>. Transmit squelch circuit <b>323</b> disconnects the inputs of amplifier <b>304</b> from inductor <b>322</b> and shorts the differential input of amplifier <b>304</b> if data-receiving unit <b>303</b> is not in receive mode. When transmitting information from the data-receiving unit <b>303</b> to data-gathering unit, inductor <b>322</b> is driven by data signals supplied by driver <b>330</b>, which is enabled by a signal COM-XMT-ENABLE* on line <b>334</b> supplied by the microprocessor of data-receiving unit <b>303</b>. Data signals to be transmitted are supplied by the microprocessor of data-receiving unit <b>303</b> via line <b>331</b>.

Inductor <b>300</b> of data-gathering unit <b>301</b> is driven by a data signal received from transmit driver <b>340</b>, controlled by input data on line <b>341</b> and enabling signal <b>342</b>. When in receiving mode signal MON-RCV-ENABLE on line <b>343</b> enables amplifier <b>344</b> which provides a received data signal on line <b>345</b> for the microprocessor of data-gathering unit <b>301</b>.

The circuits shown in FIG. 3 serve to transmit data between two devices without physical contact. The two inductors <b>300</b> and <b>322</b> are just brought into operative proximity with one another. It is understood, that certain components of the circuit of FIG. 3 can be omitted if no bidirectional transmission is required.

In the preferred embodiment of the present invention the inductor is implemented as a coreless wire coil. The diameter of the coil determines how precisely the sending and receiving inductors have to be aligned with each other for proper transmission. Instead of using wire coils the inductors can be implemented in trace form on rigid or flexible printed circuit boards.

As previously mentioned, instead of inductively generating electro-magnetic pulses or signals directly from the data signals, the data signals can be used to switch or modulate a carrier signal, and the switched or modulated carrier signal is supplied to the inductors. The receiving circuit requires a demodulator suitable for the selected modulation scheme and frequency.

The invention has been primarily described with reference to inductive coupling as the mode of contactless connection. Although inductive coupling is presently preferred, other contactless connection modes may be used, as well. A low power HF radio transmission system can be used in which the inductor coils described above are replaced by antennas of suitable size for the selected frequency range.

A capacitively coupled data transmission system may be used as well, <i>in which coils</i><b><i>212</i></b><i>and</i><b><i>234</i></b><i>of FIG. 2 are replaced by foils attached to walls</i><b><i>216</i></b><i>and</i><b><i>230</i></b><i>to act as coupling capacitor plates when brought in close proximity to each other. Data switches</i><b><i>211</i></b><i>and</i><b><i>235</i></b><i>have to be configured to drive capacitive loads instead of driving inductive loads</i><b><i>212</i></b><i>and</i><b><i>234</i></b><i>, respectively.</i>

For operation in an electrically noisy environment or for other reasons the inductors can be replaced with transmission interfaces using sonic or ultra-sonic acoustic transmitters and receivers, or optical transmitters and receivers or the like. Means for converting digital data from memory into suitable sonic or optical signals are well known in the art. The data transmitted may be coded and used directly in the transmission system, or the coded data signals may be used to pulse or modulate a carrier signal.

In this contactless data transmission system any suitable protocol for data communication can be used. One protocol which has proven effective utilizes packets of pulse width modulation bits organized into fields as shown in FIG. 4.

A packet consists of 2 byte long preamble field <b>401</b> made up of 16 zero bits to establish bit framing and data polarity.

This is followed by a 1 byte packet header field <b>402</b> made up of a header code and a packet sequence number.

The fourth byte carries the command code <b>403</b>.

The fifth byte carries the data byte count N <b>404</b> indicating the length of the following field in bytes.

The data field <b>405</b> has a length of N bytes as indicated in the preceding byte. In a transmission to the data-gathering unit, this data field <b>405a</b> may contain a request to execute a function or it may contain data to be stored in the monitoring device. In a transmission from the gathering device data field <b>405b</b> contains collected data.

The last two bytes <b>406</b> carries the EDC (error detection code) which is computed from the preceding N + 3 bytes.

In the communication protocol, the data-receiving unit <b>62</b> (FIG. 2) is the master device and the data-gathering unit, shown in FIG. 2 as <b>22</b>, is the slave. The data-receiving unit transmits a command packet requesting that a defined function or operation be performed by the processor in the data-gathering unit. The data-gathering unit then performs that defined function and responds with a reply packet containing the result. If either packet is disrupted during transmission, the command/reply sequence is repeated until successful. The execution of a function may depend on the occurrence of another event, such as a medical event or a time event. For this reason, the contents of a command packet containing information for execution of a function at a later time is stored in local memory of the processor in the data-gathering unit.

FIG. 5 is a flowchart of the data-receiving unit's transmission activities illustrating the initiation of information transfer between the data-receiving device and the data-gathering device. This illustrates a power-saving feature that is advantageously employed. It will be recognized that the data-gathering unit can be constructed to use minimal amount of power during its data-gathering activities. Data transmission, by any of the contactless methods herein described, on the other hand requires higher rates of power consumption. Since the data-gathering device is portable any decrease in overall power usage can directly reduce the size of its batteries or other power supply. It is thus advantageous if the circuit can operate in two modes - a low power-consumption slow speed first or "sleep" mode, used during data collection, and a high power-consumption second or "awake" mode, used during data transmission.

In the protocol shown in FIG. 5, after initiation <b>501</b> of communication the data-receiving unit determines whether the data gathering unit may be in slow mode (sleep mode), step <b>502</b>. The data gathering unit assumes slow speed mode about 900 msec after a transmission to the data-receiving unit. To switch a data-gathering unit into fast mode the data-receiving unit issues a predetermined number of bytes of zeroes as a wake-up call, step <b>503</b>. A command packet of a structure as shown in FIG. 4 is issued in step <b>504</b>.

The data-gathering unit responds to the command. If the response is evaluated as valid, step <b>505</b>, the command packet sequence counter is advanced, step <b>506</b>, for the next command packet transmission, and the transmission cycle is terminated, <b>507</b>.

If the received response is considered invalid (step <b>505</b>) the retry counter is advanced (step <b>508</b>). If less than six retries have been made, the command cycle is repeated (step <b>509</b>), otherwise the command cycle ends with an error flag, <b>510</b>.

FIG. 6 is a receive flowchart illustrating a data-gathering unit monitor packet transmission protocol.

The processor of the data-gathering unit idles in a low speed state <b>601</b> in which it monitors the event switches and the receive signal from the inductor coil. Events are recorded in the memory in the low speed mode. Upon recognition of received signal <b>602</b> the processor switches into high speed mode <b>603</b>.

Entering high speed mode the activity counter is set to a maximum value. Then the processor waits <b>604</b> for receiving a signal. If the activity counter times out <b>605</b> and no packet start was detected <b>618</b> the processor increments the aborted communication counter <b>620</b> and returns to wait state <b>601</b>. If a packet start was detected the processor returns directly to wait state <b>601</b>. Upon receipt of preamble and header bytes which are indicative for Start of Packet <b>607</b> the received packet information is checked and verified, <b>608</b> and <b>609</b>. Upon recognition of a packet not structurally valid the bad packet count is incremented <b>610</b> and the processor waits for the next packet in loop <b>604</b>, <b>605</b> and <b>607</b>.

A verified packet causes an increment of good packet count <b>611</b>. The desired function is executed <b>619</b>, the reply code is transmitted <b>614</b> and the activity counter is set to maximum value. Thereafter, the processor reenters the wait loop for the next packet in loop <b>604</b>, <b>605</b> and <b>607</b>.

FIG. 7 is an illustration of an electro-optical interface between data-gathering device <b>701</b> and data-receiving device <b>702</b>. Processor <b>707</b> in data-gathering unit <b>701</b> corresponds to processor <b>202</b> of data-gathering unit <b>22</b> in FIG. 2. Processor <b>708</b> corresponds to processor <b>236</b> in data-receiving unit <b>62</b> in FIG. 2. The arrangement <b>700</b> in Fig. 7 corresponds to arrangement <b>12</b> in Fig. 2 except for the differences in the implementation of the contactless communication. For bidirectional communication each of the units have a light emitting device <b>704</b> and <b>705</b> such as a light emitting diode, and a photo sensor <b>703</b> and <b>706</b> such as a photo diode. The optical elements of the electro-optical interface are mounted in conforming surfaces <b>716</b> and <b>717</b> of data-gathering unit <b>701</b> and the data-receiving unit <b>702</b>. Light emitting device <b>704</b> receives electrical signals via line <b>711</b> from processor <b>707</b>. Photo diode <b>703</b> provides electrical signals to processor <b>707</b> via signal line <b>712</b>.

In data-receiving unit <b>702</b> light emitting device <b>705</b> receives electrical signals from processor <b>708</b> via signal line <b>713</b>; light sensing device <b>706</b> provides an electrical signal to processor <b>708</b> via line <b>714</b>. Sense and drive amplifiers may be provided in the interface connections <b>711</b>, <b>712</b>, <b>713</b>, and <b>714</b> between the optical driver and sensors and the associated one of processors <b>707</b> and <b>708</b>.

Operation of the transfer of data between data-gathering unit <b>701</b> and data-receiving unit <b>702</b> can be performed in the same order and under the same protocol as disclosed above in reference to data transfer using electro-magnetic pulses and inductors.

The communication system may be equipped with a receiver for signals of a pager system. These pager signals may contain alert signals which control the generation of optical, acoustical or other types of alert signal for the user of the data-gathering unit.

In another variation of the system of this invention the user alarming functions if present may be in a patient-notable alarm device which is separate from the data-gathering unit. In this variation, the user notes an alarm and records a medical event in response to it. The alarm can be reset by contactless communication of data between the alarming device and the data-gathering unit which would have noted the medication event or a data-using unit in a similar fashion as disclosed above for the communication between a data-gathering unit and a data-receiving unit. Furthermore, the alarming device may be triggered and reset remotely from a centralized system such as using a pager system as just described, providing a communication path directly from a health care professional to the user.

In still another variation, the data-gathering unit includes a circuit for converting energy transmitted to it via separate inductors or the same inductors used for transmitting data between the data-receiving unit and the data-gathering unit. The transmission of energy may be performed independently from any data transmission or concurrent with a data transmission between the two units. The transmitted energy may be stored in the data-gathering unit such as in a rechargeable battery or a capacitor. The transmission of energy can be performed at a frequency easy to separate from the frequency band used for transmitting data from the data-receiving unit to the data-gathering unit. The energy recovery circuit used for converting the received transmitted energy to D.C. for storage in the data-gathering unit may include a circuit for deactivation when transmitting data from the data-gathering unit to the data receiving unit.

If separate inductors are used for transmitting data and energy, the two sets of inductors can be located so as to reduce or prevent interference between energy transmission and data transmission.

The inclusion of a second power supply rechargeable by wireless energy transmission allows to separate the power consuming communication operation from the low-power data-gathering operation. The so-transmitted energy can be stored for communication operations over short time spans. An energy transmission can be performed just shortly prior to an intended data transmission. The separation of power supplies for data gathering and for communication operations allows the use of smaller batteries. In such an application, the main power supply of the data-gathering unit is used exclusively for data gathering and alerting operations.

The specific circuitry and communication protocols set forth herein are merely representative. Other systems, employing the contactless coupling of this invention could be used as well.