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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to paging transmission systems and, more particularly, but not by way of limitation, it relates to an improved method of paging transmission which conveys text, coded matter and/or pictorial data with maximum
message content for reception and reproduction by means of a paging-type receiver or equivalent functioning in combination with a personal computer. In essence, the method entails the initial development of the data as binary signal data with subsequent
encoding as, for example, ASCII data which is then transmitted via a paging system and received for subsequent decoding and data output indication. The system includes yet another level of encoding by enabling an additional custom code encryption for
augmenting secrecy.
2. Description of the Prior Art
There have been many prior attempts at collection and compression of data for subsequent transmission to transmit maximum amounts of data in compressed or bandwidth reduced form, with subsequent reception at remote locations using receivers of
limited size and data reproduction capabilities. This has been particularly evident from the various attempts at transmitting electrocardiogram (ECG) information for subsequent data analysis and diagnosis. One such approach to the storage and
transmission of ECG data is disclosed in a paper entitled A New Data Compression Algorithm for Computerized ECG Signal by Walter H. Chang and C. D. Kao which appeared in IEEE/8th Annual Conference of the Engineering in Medicine and Biology Society, pages
311-314, under copyright in 1986. This paper is specifically related to transmission of ECG data and the method of doing so utilizing signal compression using the Huffman Minimum Entropy Coding Method to attain increased data reduction ratio. This
method succeeded in transmitting and retrieving ECG data of twelve leads per patient along with a 30 second rhythm strip record and other pertinent data; however, the system required a mass of storage medium and an inordinate amount of time to deal with
such a large amount of data, even when reduced by data compression.
Current paging systems carry minimal information for reception and indication at remote positions; however, this information carrying capacity is extremely limited. Any attempt to transmit extensive data or text messages by the present day
national paging system hook-ups, i.e., EMBARK (Motorola) or SKYTEL (MTEL), would be cost prohibitive without extensive alterations to the transmit/receive systems.
SUMMARY OF THE INVENTION
The present invention relates to improvements in coding and transmitting message data for reception by a pager device having data storage and downloading capability in combination with a digital computer. More particularly, the device employs
software controlling both transmission and reception of data to enable reduction of complex, multifaceted information to a transmittable data form with subsequent reception of the data through a paging system receiver for intermittent download, decoding
and recomposition of the data through an associated computer. In essence, data from a selected source is converted to binary code and then translated into an alphanumeric code and, if the data message is of sufficient length, the alphanumeric code data
is divided into sequential sub-files which are then presented to a paging switch in succession for transmission. The transmitted data is received by a paging receiver with sub-file storage, and the data is downloaded to an associated palmtop computer
for file reconstruction and subsequent alphanumeric code to binary translation for reproduction of the data message information.
The total secrecy of the transmission system is increased and reinforced by the addition of a custom code encryption which adds yet another level of encoding. The coded source text or data is encrypted in the source computer in accordance with a
custom code of specific type and application (for example, the National Bureau of Standard, Data Encryption Standard (DES)). Upon reception at a paging receiver, the encrypted and coded data is conducted to an associated computer (e.g., palmtop) which
carries out decryption and decoding of the message text for display presentation.
Therefore, it is an object of the present invention to provide a paging transmission system that is capable of transmitting complex data to a remote position for reception by a paging receiver to enable reconstitution of the complex data for
usage, observation, etc.
It is also an object of the present invention to provide an improved paging transmission system that has large volume information capability.
It is yet further an object of the invention to provide novel computer software for increasing the function and capability of existing pager transmission hardware.
Finally, it is an object of the present invention to provide a relatively simple and reliable paging transmission system that is capable of rapidly transmitting various forms of data including medical data, digitized image data, speech, radar
indication, seismic data and actually any data that is capable of being sensed and reduced to binary data form.
Other objects and advantages of the invention will be evident from the following detailed description when read in conjunction with the accompanying drawings which illustrate the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a broad function block diagram illustrating the crux of the present invention;
FIG. 2 is a block diagram showing the transmitting portion of the paging transmission system;
FIG. 3 is a block diagram showing the receiving portion of the paging transmission system;
FIG. 4 is one form of paging receiver/palmtop computer that is suitable for use in the present invention;
FIG. 5 illustrates one example of electrocardiograph data acquisition system that is suitable for use with the present invention;
FIG. 6 is a program flow diagram for providing electrocardiograph data acquisition for the present transmission system;
FIG. 7 is the program flow diagram succeeding FIG. 6;
FIG. 8 is the program flow diagram succeeding FIG. 7 and controlling final data transmission;
FIG. 9 is a program flow diagram for the encode operation set forth within the flow diagram of FIG. 8;
FIG. 10 is the flow diagram for the first part of the software for receiving, decoding, displaying and analyzing received electrocardiograph data;
FIG. 11 is a portion of flow diagram succeeding that of FIG. 10;
FIG. 12 is a third succeeding portion of flow diagram relating to the receiving function;
FIG. 13 is a flow diagram for the decode operation as set forth in FIG. 11;
FIG. 14 is a block diagram showing an alternative form of paging transmission system; and
FIG. 15 is a diagram of an alternative form of paging receiver combination.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates the basic paging transmission system 10 in its broad process steps. The data source 12 may represent any form of real world data that is measurable and susceptible of being embodied as a sequential binary coded signal. While
the paging transmission system 10 has been specifically adapted to the transmission of ECG signals, as indicated by the various drawing and flow chart designations; it should be understood that data source 12 may produce any of various forms of message,
i.e., text, pictorial or graphic data material and there is virtually no limitation as to the type and length of subject matter. For example, some benefits that business users may enjoy include the ability to receive wireless information such as: (1)
messages and electronic mail; (2) voice mail notification; (3) data base information; (4) updates sent directly into appointment and phone book files, worksheets, calendars, to-do lists and memos; pictorial and graphic data; and (5) travel information
including flight data, car and hotel arrangements, etc.
The data source 12 provides output indication of its data content to a stage 14 where the data, already in binary coded form, is translated into a 7-bit ASCII code format (plus start and parity bits) that is compatible with all standard forms of
paging system. If the message length requires, the 7-bit ASCII coded data may then be divided into sequential sub-files in generation stage 16. The maximum size of the sub-files is only limited by the storage capacity of the paging receiver, as will be
further described, and the number of sequential sub-files to be transmitted is virtually unlimited.
The use of ASCII coded data is specified herein because that code is provided for by the Telocator Alphanumeric Protocol (TAP) which has been adopted as standard by the United States central paging terminal manufacturers association for input of
numeric, alphanumeric, or tone only pages sent from a binary output device to a central paging terminal. Thus, while ASCII is referred to in the specification and drawings, it should be understood that other recognized five and seven unit codes (e.g.,
IBM Transceiver Code, CCITT 5 Code, EBCDIC Code and others) may be substituted with proper allowance in the system programming.
The successive sub-files from generation stage 16 are then transmitted via modem and the standard Telocator Alphanumeric Protocol to the paging switch for transmission at pager transmission stage 18. A single phone line connection will place the
sub-file data at the paging switch for transmission. Thus, a single personal computer and appropriate software converts binary data into 7-bit ASCII format, and divides into sub-files if necessary, whereupon the data is transmitted via pager
transmission 18.
A pager receiver then receives the data in ASCII format, with or without sub-file sequence, via wireless transmission for subsequent pre-processing and connection via RS-232 or other form of data connector interface to a standard form of
computer. In this case, a laptop or even more miniaturized palmtop computer with adequate storage is desirable, and the computer is programmed to carry out file reconstruction at stage 20 wherein all received and stored data sub-files are sequentially
downloaded to the computer and reordered into proper ASCII message format. At stage 22, the ASCII code or other code sequence is translated to a binary signal sequence which is then conducted to output 24 for conversion to text, voice, pictorial output,
or other message embodiment.
This message sequence is carried out by the standard type of paging system transmitter coupled with a computer that prepares the data through the binary signal to ASCII code conversion with sub-filing sequence as the software can control.
Thereafter, the receiving pager is preferably one having some portion of internal storage and which is connectable via RS-232 or other data connector to a palmtop computer. As an example, the receiver may consist of a Motorola NewsStream.TM. paging
receiver coupled with a Hewlett-Packard palmtop computer, Type HP95LX. While this paging receiver/palmtop combination is especially desirable for use in the paging transmission system 10, it is by no means indispensable because any of a number of paging
receivers and palmtop computers can be compatible for functioning in accordance with the method of the present invention.
Referring now to FIG. 2, the transmission portion of paging transmission system 10 is illustrated in greater detail. A data acquisition system 26 functions to gather the basic data for conversion into binary code format (either 8, 12, or 16-bit
data) for input to a control computer 28 at the transmitting station. The data measurement stage 30 may consist of some form of data sensor and readout, along with a voice pickup 31 and image scanner 33 or the like, which provides signal output to an
analog to digital converter 32 that provides digital output to an encoder 34. Encoder 34 then translates the data to a binary code format which may be output at connection 36 by either RS-232 hardline connection, wireless or other line connection as
input to computer 28. Optionally, measured data permitting, encoder 34 may be bypassed with direct input of data on lead 38 either into data compression stage 40 or into ASCII conversion stage 42. In either case, the data eventually gets converted to a
prescribed code format, e.g., ASCII, at stage 42 and, if necessary, the ASCII data is divided down in divide stage 44 for storage as data sub-files in storage 46. Still another option is for the data to be initially received in ASCII format from stage
47 and applied directly to divide stage 44.
Stored data sub-files 46 are then read out on line 48, and any identity data is added at stage 50 as the data sequence is input to a standard modem 52. The data message is then input via modem 52 to the paging switch 54 for subsequent
transmission by transmitter 56 at the requisite paging transmission system frequencies and modulation.
Referring to FIG. 3, the transmitted pager information is then received at the pager receiver 58 as indicated at stage 60 and the data is downloaded at stage 62 for input via connection 64 to a computer 66, for example the Hewlett-Packard Type
HP95LX palmtop computer. The connection 64 may be by any of several modes, as will be further described, which are made possible currently by using the Type HP95LX in combination with the Motorola NewsStream.TM. data receiver. At present, the paging
receiver used is the Motorola Type A05KQC4373AA having a frequency range of 929-932 MHz and a total memory size of 32K bytes.
In palmtop computer 66, the data connection 64 applies downloaded ASCII data and stage 68 functions to recombine the data sub-files into proper sequence. Stage 70 then retranslates the data file from ASCII format to binary signal data which is
then compatible for output to any of data display 72, printout 74, further processing 76 and/or audio output 75.
FIG. 4 shows a present form of compatible combination of pager/receiver 58 and palmtop personal computer 66. A special portability holder 80 is formed with left and right channels 82 and 84, respectively, and these are divided by a bar 86 which
includes a release button 88 and feed through connector type RS-232 (not shown). The Type HP95LX palmtop computer 66 is lockable within channel 82 and the paging receiver 58 (NewsStream.TM. type) is lockably received in channel 84 as a feed-through
connector (not shown) makes proper connection between the two units. The computer 66 and paging receiver 58 are also releasible so that they may be separately deployed, and the NewsStream.TM. paging receiver includes up to 32k of storage so that it can
receive and hold messages for subsequent engagement in holder 80 to download its contents to the associated computer 66.
FIG. 5 illustrates the situation wherein the present paging transmission system is employed for transmission of electrocardiogram (ECG) information. Thus, a patient 90 is connected by a multiple of sensing wires 92 (usually ten) for input to a
standard type of ECG machine 94. The ECG machine 94 includes a binary data conversion stage as well as a slot 96 for receiving a floppy disk such that previously recorded ECG information may be conducted variously to an output computer 98. The output
from ECG machine 94 may be recorded on the floppy disk in slot 96 so that disk transfer function 100 will place the disk in computer 98 in readiness for readout. Second, the ECG data may be directly applied by wire connection 102 for input to the
associated computer 98; or third, the output from ECG machine 94 may be via phone line connection 104 to a modem 106 which transmits the ECG data via phone connection 108. The computer 98 then may further process the data to an ASCII form for connection
through a modem 52 and paging switch 54 (FIG. 2) whereupon the ECG data is transmitted via wireless link.
The program controlling the unique function of the above-described hardware is set forth in the following figures as will be described. The description proceeds relative to use of the invention in an ECG surveillance and reporting mode; however,
it should be understood that the paging transmission system will find use in very many modes of business activity. FIG. 6 illustrates a start point in the paging transmission system transmitter for the case wherein ECG data is to be processed. At
process start, the flow indicates initialization as variables, constants and arrays are initialized at stage 110, the memory for ECG data is allocated at stage 112 and the graphics system is initialized at stage 114.
Proceeding in FIG. 6, the flow steps bracketed by 116 all relate to initial setup of the transmission station digital computer 28 (FIG. 2) for receiving the ECG input data. Thus, lead selection alignment and x-axis data allotment are created for
each of the multiple leads of ECG data, in the normal case twelve lead data. Flow stage 118 then functions to load the raw ECG data into the computer memory and the raw data is filtered if necessary in stage 120. If data quality permits, the filter
stage 120 can be bypassed via flow line 122 and processed through a next optional flow stage 124 wherein the ECG data is decimated with consideration of the sampling frequency. That is, the second optional stage 124 allows pre-examination of the data
and a choice to throw out certain redundant or unnecessary data points thereby to reduce the overall data; or, flow stage 124 can also be bypassed with information on flow line 122 being applied directly to the flow stage 126 to display the twelve lead
ECG wave forms on the data screen.
Program flow then proceeds to FIG. 7 and flow stage 128 which implements scanning of the individual ECG data wave forms as a series of decision stages are effected. Stage 130 queries as to whether or not the keyboard is hit and if not the output
is via flow line 132 back for recycle through the scan operator command stage 128. If decision stage 130 shows affirmative then flow proceeds to decision stage 134 which queries whether or not the data is to be written to file. If affirmative, then the
output file for selected ECG data segment is readied at flow stage 136 and data operation flow recycles on line 132 for scan of the next successive operator command in flow stage 128. If the write to file question shows in the negative, then flow
proceeds to decision stage 138 to determine whether or not there is a match between the selected ECG segment and the arrow designators. If affirmative, flow proceeds to stage 140 and the arrows align with a new segment of raw ECG data files. If
negative, the zoom operation is selected in stage 142 to display the respective lead selection cursor and, when the lead is selected at decision stage 146, the process stage 148 displays the selected lead of ECG data. Returning to flow stage 140, when a
new segment of raw ECG data is pointed, the flow recycles to FIG. 6 and the input No. 2 to the flow stage 118 to load additional raw ECG data into memory, which data relates to the new segment. The new segment of data is then passed through the optional
flow stages 120 and 124 or in bypass on flow line 122 for display as one of the multi-lead ECG wave forms on the screen at flow stage 126.
From flow stage 148 of FIG. 7, the operation proceeds to FIG. 8 and interconnect No. 3 to a flow stage 150 which converts the selected ECG data segments from binary to ASCII code data. The program for encoding the selected ECG segment of stage
150 is shown in greater detail in FIG. 9. Thus, the encode function starts with reading of the binary input file and counting of the total number of bytes (N) at flow stage 152 and creation of text output file at stage 154. The program initializes a
pointer (X) at a value of X=1 at stage 156. Flow stage 158 then reads the (X) to (X+2) bytes of binary data from the binary input file.
Flow stage 160 then transfers the contents of the consecutive three binary bytes into four ASCII bytes at byte positions (X) to (X+3) so that only the least six bits of the ASCII bytes are occupied. In flow stage 162 the function is to add 32 to
every ASCII byte generated and in stage 164 the 4 resulting offset ASCII bytes are written to the text file. Flow stage 166 then sets N=N-3 and a decision stage 168 queries for correct data content. If data content is correct then affirmative
indication to end of file stage 170 will proceed to close files stage 172. If, at decision stage 168, the N=0 query is negative, flow recycles via line 174 for reentry to flow stage 158 after the value of X is incremented X=X+3 at stage 176. The
program then again transfers the contents of the next consecutive 3 binary bytes into 4 ASCII bytes thereby occupying only the least six bits of the ASCII bytes. When all multi-lead ECG data has been encoded, affirmative output from end of file decision
stage 172 effects closing of files at 174 to stop the encoding process.
The software for encoding (FIG. 7) and decoding (FIG. 13) the pager transmission data is included herewith as:
Exhibit 1: PC Software; and
Exhibit 2: HP95LX Software.
Returning again to FIG. 8, the flow stage 180 functions to split the encoded ECG segment data in the form of ASCII code into messages that are suitable for paging. That is, messages that have proper content for sequential passage through the
transmission system without overloading receiver storage. A transmitted file may contain not only the twelve lead ECG data but also important information as to the patient's age, sex, blood pressure and other pertinent history. The total data file is
sub-divided into separate sub-files for transmission, the exact number and size of the files to be determined by the program limits of the paging system. Each of the sub-files contains some redundant information in order to deal with inevitable
transmission errors. For instance, the phone number of the particular emergency room is sent in each sub-file and can be reconstructed on an error-free basis even if all files are sent with data corruption. This feature allows a receiving cardiologist
to call the sending emergency room to request a re-transmission of the ECG data, if necessary. At flow stage 182, the paging transmission system is prepared to transmit the ECG data. Then, in flow stage 184 the ECG messages are each individually
transmitted in sequence until end of transmission is signified at flow stage 186.
The flow diagram of FIGS. 10, 11 and 12 illustrate the operation at the paging receiver 58 and computer 66 (FIG. 3). In FIG. 10, the flow stages within bracket 190 indicate initialization of variables and constants, allocation of memory for
received ECG data (a single file) and initialization of the associated graphics system. The display graphics are created in flow stage 192 as the twelve-lead ECG data can be selectively presented and flow stage 194 sees to the X-axis data vector
placement. The computer screen is properly set up and formatted for twelve-lead data at stage 196 and incoming messages are read at stage 198 for search at stage 200 to detect any incoming ECG data messages.
Referring to FIG. 11, the program proceeds to flow stage 202 wherein the successive sub-file messages are joined to form the complete message, if in fact more than a single sub-file was required. Thus, the ECG ASCII message code files are formed
into a single file. Thereafter, this single file message is decoded in flow stage 204 as illustrated in FIG. 13. The process of FIG. 13 is essentially the reverse of the encode routine of FIG. 9. In FIG. 13, decoding commences with opening of an input
file in the text mode at flow stage 206, counting of the total number of bytes N, and subsequent creation of a binary mode output file at stage 208. Any header information is read and removed from the recombined ASCII file at stage 210, and a data file
pointer Y is initialized to Y=1 at stage 212. Stage 214 effects reading the Y to Y+3 bytes of encoded data. Stage 216 sees a subtraction of a value of 32 from each ASCII offset byte thereby creating new ASCII bytes.
In flow stage 218, three binary bytes are generated for every 4 ASCII bytes that are read by increasing to eight the number of binary bits that are occupied by the least significant six bits of ASCII bytes. Flow stage 218 writes the binary bytes
to a binary file. Process stage 220 then sets N=N-4 as flow proceeds to decision stage 222 to test for N=0. If negative, flow recycles to flow stage 214 to process the next 4 bytes of data. If decision stage 222 queries affirmative, then it proceeds
to declare end of file at stage 226 and the decoding process stops.
Referring again to FIG. 11 the decoded binary file data is loaded into ECG data memory at flow stage 230, and flow stage 232 displays the 12-lead ECG data on the computer screen. That is, the graphics screen 72 of the portable computer 66 (see
FIG. 3). The attendant operator may then select an individual ECG lead for enlarged zoom display, an inherent and necessary function for the diagnostics usage. The user's command from flow stage 234 is decoded in flow stage 236 and flow stage 238
queries as to whether or not to scan to the next lead. If affirmative, flow line 240 recycles to stage 236 to decode user's command, and if decision stage 238 is negative, then flow moves to decision stage 242 to pan the data to the next time segment
that relates to a selected lead. Upon decision, negative response moves to interconnect No. 2 via flow line 244, and affirmative response on flow line 246 effects panning to the next time segment at stage 248 with recycle flow via line 250 to flow stage
236 and a wait for decoding of user's command.
Referring to FIG. 12, flow line 244 proceeds to flow stage 252 to bring in the ECG measurement screen, and flow stage 254 enables interactive display of cursor movement on the ECG waveform in response to the user input moving the cursor key 255.
Flow stage 256 provides indication of cursor location in time and amplitude subject to flow stage 258 and the interactive second cursor 259 movement. ECG measurements in time and amplitude are effected in flow stage 260 and recorded as at flow stage
262. Decision stage 264 then queries as to whether the process should end and, if affirmative, it proceeds to stop.
If decision stage 264 tests negative, then process proceeds by flow line 266 to input interconnect No. 3 on FIG. 11. The recycle input from interconnect No. 3 is to the flow stage 236 to wait for decoding user's command. Thus, decision stage
238 selects a next ECG waveform or time segment thereof for processing through the measurement program of FIG. 12, i.e., the flow stages 252-262 and so on until decision stage 264 signifies quit or cease processing.
In operation, the present paging transmission system offers increased advantage in those situations where a significantly large amount of text, graphic, voice or combination data must be transmitted to an authoritative or diagnostic person or
persons in order to obtain a clarification or instruction to proceed. For example, in the case of ECG information, a patient may be disposed in an emergency room with continual ECG data being recorded while the attending cardiologist or medical doctor
is at a remote location during either leisure hours or work activity at a different location. It is only necessary that the doctor have with him the combination paging receiver 58/palmtop computer 66 such as illustrated in FIG. 4.
The method of the present invention is capable of sending, receiving and displaying physiologic data of both textual and graphic type. The system can transmit all forms of ECG data including 12-lead ECG data, signal averaged data,
transtelephonic rhythm strip data, Holter monitor data and direct connect or telemetered rhythm strip data. Various other forms of physiologic data such as fetal monitoring, End Tidal CO.sub.2 data, Pulse Oximetry data, Cardiac Output data, etc. may be
transmitted using the present method.
Data may be obtained directly from a patient via a medical diagnostic or monitoring device for digitization and binary encoding into code form compatible with the paging transmission system utilizing the standard TAP protocol. The transmitted
data may include any graphic data such as waveforms, X-rays, depictions etc. while also including alphanumeric text data identifying patient's name, any demographic and/or clinical patient data, telephone number and location or ER from which data is
being sent, as well as data check number of files, rank of each subfile, number of characters per subfile, etc. An error detection scheme may be included such as a three-digit checksum to identify continually each data subfile transmitted. Also, it is
important to include the source telephone number in each subfile so that a redundancy test will always allow reconstruction of the correct source telephone number, and thence the source location, even with missing or corrupted subfile data.
In the event of a problem or other emergency indication detected at the emergency room, the appropriate data can be measured, digitized and encoded in the ASCII code for transmission via modem to the paging switch 54 and transmitter 56 (FIG. 2).
The real world data may include such as multi-trace (12 lead) ECG data, one or more lead monitored rhythm strips, signal averaged ECG waveform, high resolution waveform data, pacemaker and other patient data. The diagnostic information is transmitted in
sufficient detail to enable diagnosis of acute myocardial infarction as well as many cardiac diseases, the diagnosis of arrhythmias and the causal ischemia, the diagnosis of a risk of ventricular tachycardia, as well as pacemaker function and other heart
or circulatory related activity.
No matter how remote the doctor's location within the transmission area, his paging receiver 58/computer 66 (FIG. 4) will take over in the manner of FIG. 3 to receive the data for download to the computer 66. If the total volume of data exceeds
the storage capacity of the pager data receiver 58 (32K bytes) as would usually be the case with ECG waveform and textual data, then data download stage 62 is effected in several increments of storage and download to the PC computer 66. Computer 66 then
recombines the ASCII code data sub-files in succession to put together the total ECG message data which is then retranslated in stage 70 to a binary coded form for replay through any of data display 72, a printout 74, or some designated further
processing 76.
It should be understood that more often than not there will be a situation where the binary file is converted to ASCII code data which is then subjected to the ASCII sub-file division and subsequent reconstruction. However, there is available an
alternative in programming choice where the initial binary file undergoes the sub-file division and generation, and then is converted from binary to ASCII code form. If this option is selected, the program must accommodate computation and reservation of
sufficient storage space for the ASCII data, or to select some designated minimum amount of storage space.
The paging transmission system as set forth in FIGS. 2 and 3 has been particularly described with respect to medical data transmission; however, there are a great many other commercial applications wherein the paging transmission system can be
utilized. For example:
(1) Sending WordPerfect.RTM. (and other word processing) documents to a mobile computer for editing and printing (e.g., customizing quotes, orders, contracts, etc.) at a site using the latest "template" from the home office.
(2) Sending Lotus 123 and other spreadsheets to a mobile computer in the manner described above.
(3) Sending digitized image matter to a mobile computer (e.g., sending pictures of homes that fit a particular buyer directly to a realtor in the field).
(4) Sending voice mail directly to individuals no matter where they are.
(5) Police use wherein a central dispatcher can continually disseminate various graphic and textual data relating to suspect identity, missing persons, etc.
These are only five of a great number of applications wherein the paging transmission system of the present invention may be utilized to good advantage.
FIGS. 14 and 15 illustrate an alternative application of the invention wherein an extra level of encoding is allowed for secrecy purposes since maximum message security is of the essence. Thus, in many official applications, e.g., secret
transmission of government or law enforcement messages, defense documents, and many other areas of governmental and industrial communications, it is necessary to have utmost secrecy as maintained by proprietary or custom codes that are rigidly controlled
by the using entity. The present paging system contemplates the inclusion of such custom codes by providing yet another level of encryption in the paging transmission/paging reception and signal processing scheme. In addition to generation of binary
data representative of given text, and subsequent translation of binary data to ASCII data for pager transmission and reception, the system now provides for options of data decompression and/or data encryption for the transmission process. Selected
equipment at the paging receiver/computer can then decompress and/or decrypt the data as required to deliver the final text message.
Referring to FIG. 14, the transmission equipment includes the same data acquisition stage 26 which may include an image scanner 33, voice pick up 31 or other data generator, all of which operate into an analog/digital convertor 32 (see FIG. 2).
Output from the analog/digital convertor 32 is via encoder 34 which produces binary coded output signals on lead 36 for input to the computer 28. The data on lead 36 may be applied optionally to a lead 230 to data compression stage 40 and then via lead
232 to the nex | | |
