in fig1 a cell phone 1 of the invention is equipped as a cardiac monitoring device , possessing a forward facing , first , head - contacting sensor 2 positioned to contact the face or ear of the user . while sensor 2 is shown in fig1 as being below the earpiece 17 on the cell phone , it may otherwise surround such earpiece 17 or be positioned elsewhere on the cell phone 1 to conveniently contact the user &# 39 ; s head during or between telephonic transmissions . to capture ecg signals , a second , side or rear - facing , hand - contacting sensor 3 is positioned to contact the left hand or thumb of the user . and preferably , a reference electrode 4 is positioned on the cell phone 1 to contact either the face or hand of the user . the electrodes may be ohmic or capacitive , the reference electrode being preferably ohmic of the active type . it is desirable in the case where ohmic electrodes are used for the first and second electrodes , particularly in conjunction with a differential , common - mode noise rejection circuit , for the body - contacting surface of such electrodes to have a volume resistivity in the range of 10exp5 to 10exp11 ohm - cms , more preferably 10exp6 to 10exp10 ohm - cms . with such an electrode it is desirable to feed the signal directly into a preferably on - board , high impedance amplifier — hence constituting an active electrode . in fig2 an already - existing cell phone 1 is provided with a harness incorporating a first , forward - facing sensor 2 positioned to contact the face or ear of the user ; a second , side or rear - facing sensor 3 positioned to contact the left hand or thumb of the user ; a reference electrode 4 , preferably ohmic , positioned to contact either the face or hand of the user ; and an electronic circuit 5 to condition and / or analyse the bio - signal and to digitise and / or modulate the bio - signal in preparation for transmission . a coupling connector 19 delivers the bio - signal to the cell phone input for telephonic transmission 18 . optionally , an input switch 10 may be provided to allow the user to select bio - signal data transfer a or voice transmission b , as shown in fig6 . fig3 illustrates a device of the invention in use by a user . when the device 1 is held to an ear as shown in fig3 , bio - signals are acquired from the same user posture as in ordinary telephonic use . use of the left hand is preferred for ecg pickup as this produces a stronger signal for most persons . but this is not a universal rule . if for any reason this posture is not convenient on a particular individual , then the invention can also be made to operate by placing the face - oriented sensors on other body parts such as the chest or opposed hand . fig6 illustrates a functional block diagram of the invention removed from the interior of a cell phone , or case for clarity . the outputs from the first sensor 1 , the second sensor 2 , and the reference electrode 3 , are connected to the conditioning circuit 5 . circuit 5 may include analyser means 15 to partially analyse the bio - signal . for the purpose of ecg pickup , the analyser circuit 15 preferably includes a differential amplifier . the analyser circuit 15 may also include means to derive key parameters from the bio - signal , provide band - pass filters , interference filters and produce outputs based on the correlation of multiple bio - signals . the reference electrode 3 is connected to circuit 5 and is also connected to a recommended electrical shield 14 , which overlies the circuitry of the invention in order to maximize the rejection of unwanted electrical interference signals . it has been found useful in some cases to overly electric shield 14 with an additional magnetic shield 11 constructed of mu - metal foil or sheet . this further reduces interference arising from transmission of the telephonic device . bio - signals that have been analysed within the circuit 15 may be provided to the memory 6 , and subsequently to the modulator 7 within the conditioning circuit 5 which prepares the signal for submission to the telephonic device input 9 . the conditioned signal may be in acoustic or electronic form ., electronic being indicated . before submission to the telephonic input 9 , however , the modulated bio - signal may be temporarily stored in a buffer memory 6 , which is also connected to a controller 8 . controller 8 controls the timing of the data submission into the telephonic device and uses memory 6 to prevent loss of bio - data . buffer memory 6 can optionally be made to store or archive several seconds of the patient &# 39 ; s ‘ normal ’ bio - signal in an archive memory 6 a . such a signal can be recorded under highly controlled conditions , such as at the doctor &# 39 ; s office , during the patient &# 39 ; s optimal health condition . this ‘ normal ’ signal can be permanently stored and sent to the doctor &# 39 ; s office along with each real - time bio - signal transmission , e . g . interspersed . such a feature would provide the health practitioner with the user &# 39 ; s ‘ standard ’ bio - signal , thus assisting the practitioner in assessing the patient &# 39 ; s immediate status . in the embodiment described previously wherein the invention is in the form of a harness or case to be used with an existing cell phone , the micro - controller 8 can be connected to a user - activated switch 10 . in this case , the switch 10 controls a sense circuit in controller 8 which toggles the cell phone through input 9 between of normal voice mode and data transmission mode . the detailed functioning of controller 8 depends on the particular model of cell phone utilized . communications over the telephonic link can be effected in a number of electronic modes . half - duplex allows the health practitioner to talk to the patient , and to instruct the patient on when to begin and cease sending the bio - signal information . when instructed , the patient switches back to ‘ normal ’ mode to regain control of the outgoing audio channel and can immediately converse in a normal fashion with the monitoring station . it is also anticipated that the monitoring station could control the bio - monitoring functions by sending a specific tone or other signal through antenna 21 and link 16 to instruct the device to begin or cease sending bio - signals , thereby removing the need for the patient to activate the device . other envisioned voice - over - data capabilities include full - duplex , via time - division multiple - access , code division multiple access or frequency division multiple access . other systems such as gprs ( general packet radio service ), edge ( enhanced data rates for gsm evolution ), high speed internet , piggy - back dsl ( digital subscriber line ) or adsl ( asynchronous dsl ) continue to expand the possibilities for simultaneous data and voice . as high - speed digital systems continue to proliferate , it is expected that more opportunities for simultaneous transmission of medical data and voice signals will arise . this will not be limited to cellular phone or pstn systems , but will also encompass cable - television , satellite , micro - cell and pico - cell communication systems . it is also envisioned that a medical telephones could incorporate two , separate voice and data systems that operate completely independently . this will allow the voice portion to connect to a pstn system and the data portion to connect to any available digital connection including , but not limited to , wired connections , wireless connections , ethernet , rs232 , usb , 802 . 11 or blue - tooth . fig4 depicts a pictorial schematic layout for an electrode used to pickup signals originating inside a body 12 for delivery to the conditioning circuit 5 . the electrical signal inside the body can be called the body - source , as represented by a voltage vb . analyzing this circuit for its dc characteristics , the body source , along with the voltage divider required for the pickup of the bio - signal is illustrated in fig4 wherein : rs and r &# 39 ; s are the skin resistance ; f is the location of the body - to - electrode interface ; rc is the contact resistance at the interface f ; re is the electrode bulk resistance , and ra is the resistance across which the output signal va is measured . the end of the voltage divider , opposite to the electrode , is connected to the body through resistance rr at point k . an operational amplifier , ic 1 a , serves as the sensing electronics . in the case of passive electrodes connected to an ecg machine , ra represents the ecg machine input resistance . in the case of active , ohmic pickup electrodes possessing an on - board , internal buffer amplifier acting as an impedance converter , ra represents the combined resistance of the sensing circuit as bridged by the sensing resistor . in order to protect the sensing circuitry from overload voltages , ra may be paralleled by two parallel , reversely oriented diodes such as diodes exemplified by panasonic ma198ct . diodes d 1 , d 2 are shown in fig5 . at the low signal levels provided by the pick - up electrodes , such diodes exhibit high forward resistances , having a resistance of on the order of 10 exp 12 - 13 ohms . the forward resistance of these diodes before conduction occurs at low voltages is on the order of 10 exp 13 ohms . by choosing diodes with a forward breakdown voltage that is above the level of the signal of interest , the “ reset ” function of the input resistance of the high impedance amplifies can be improved . fig5 shows a differential input electronic circuit that reduces or eliminates common mode noise . in fig5 two pick - ups using operational amplifiers ic 1 a , ic 2 a similar to that of fig4 are used to drive a differential amplifier ic 3 a which further conditions the signal for transmission by shielded wire 20 to a further portion of the conditioning circuit 5 , and eventually to the telephonic communication circuit of the phone . by use of this differential signal detection circuit , common mode noise arising from the reference electrode , the body , and external noise sources will be minimized . in summary , using the invention a new and useful means for telemonitoring of patients may be provided . the foregoing has constituted a description of specific embodiments showing how the invention may be applied and put into use . these embodiments are only exemplary . the invention in its broadest , and more specific aspects , is further described and defined in the claims , which now follow . these claims , and the language used therein , are to be understood in terms of the variants of the invention which have been described . they are not to be restricted to such variants , but are to be read as covering the full scope of the invention as is implicit within the invention and the disclosure that has been provided herein .
a bio - monitor is built into a telephone handset or cell phone . sensors are configured to obtain bio - signals while the handset or cell phone is in the position for normal speaking use of the telephonic device . this enables biosignal acquisition and / or bio - signal telephonic transmission to occur without the need for a position change to effect voice communications . the invention can also be constructed in the form of a case or harness designed to fit over a preexisting cell phone or a pre - existing telephone handset .