Field of the Invention

The present invention is in the area of paging systems and pertains in particular to the portable receiving units called pagers that are carried by users to alert them someone has called them.

Background of Invention

Portable receiving units, termed "pagers" and sometimes "beepers" in the art, alert users that someone is trying to reach them on the telephone. Pagers are most popular among salespersons, tradespersons, and messengers but also are heavily used by doctors, lawyers, and other professionals who are away from their telephones but need to stay in touch with clients.

Pager devices are typically battery-powered with electronic calculator-type, integrated transistor circuitry. A user subscribes to a paging service that provides local, regional, and/or nationwide network coverage. The paging service receives a page call from some single source, such as a satellite telecommunications network or leased telephone line transmission, and instantly broadcasts the paging signal from a number of radio-frequency transmitters in the subscription area.

The radio signal is received by the pager through a miniature antenna inside the device and demodulated to digital form by the pager's circuitry. In turn, the pager alerts the user with a blinking light, beep, chime and/or vibrational signal that a call has been received. The pager then typically conveys the message through a small liquid crystal display (LCD) through which a numeric message (the caller's telephone number) or an alphanumeric message (words and numbers, such as "CALL OFFICE BEFORE 5

PM") is displayed. The user may then use his/her cellular telephone or a nearby stationary telephone to return the call.

The LCD display is convenient for the user, who needs to know the number of the party that called and/or the caller's message. One drawback is that LCD displays are expensive and bulky.

The desire of manufacturers to follow the trend to miniaturization in a highly competitive market has led to the creation of a "tonal" pager. The tonal pager is so small it can be built into a wristwatch, an example being the Piepser watch/pager marketed by a joint venture between BellSouth MobileComm and Swatch Watch Co. The small size is possible because the tonal pager does not have an LCD display as a user interface. Instead of an LCD display the tonal pager outputs distinctive audio tones to identify the caller. The Piepser pager is capable of receiving signals from a limited list of telephone numbers, typically no more than four. Each of these telephone numbers is preassigned a unique tone identifier, for instance, one beep will identify one particular caller, two beeps, another, and so on. By prearrangement the user knows the telephone number to call for each tone identifier.

A variety of innovations have been evidenced in pager development over the last few years. The concept of the tonal pager with its audio user interface, as described above, is one advancement in the art. However the tonal pager described has a drawback in that it can only respond to a few callers, being self-limited by the number of tones the device generates. The tonal pager in its present state has a market with users who need to keep in contact with only a few parties but it does not answer the needs of business users with growing clientele lists.

Another drawback of conventional pagers is that they

do not have an autodial call-back capability. In most, a display is required for the user to read the call-back number, then the user has to dial the number. In the Piepser pager, although a display is not used, the lack of the display limits the concept to just a few numbers.

What is needed is a tonal pager that can receive calls from an unlimited number of callers and automatically dial callers' numbers. Both of these needs could be realized with the use of DTMF tone conversion technology to autodial numbers. In addition, such a pager might have a voice synthesizer to speak the calling number upon request so the user will know who made the call.

A voice pager that dials the number to be called and/or that speaks the number to be called has great utility for vision-impaired people.

Summary of the Invention

In a preferred embodiment of the present invention a dialing pager is provided comprising an antenna means for receiving a paging radio signal which includes a telephone number for a user to call, a demodulator for converting the received radio signal to a digital form, a CPU means configured for managing the functions of the pager, memory means for storing the digital form of the received radio signal, and DTMF generation means for producing DTMF signals. There is a bus communication means linking the demodulator means, the CPU means, the RAM, and the DTMF generation means. In addition, an activation means operable by a user is provided for initiating retrieval of the stored form of the received signal and for providing the telephone number to the DTMF generation means for conversion into a string of corresponding DTMF tones. A speaker connected to the DTMF generation means provides

audible DTMF tones corresponding to the telephone number for dialing the telephone number.

With the dialing pager of the present invention, after receiving a page, one need only hold the pager proximate a telephone mouthpiece and key a playback button to initiate the DTMF string to dial the phone. A display in this embodiment is not needed, and the size and cost of the unit is minimized while retaining the full function of conventional pagers.

In alternative embodiments a display is provided so a user can check the callback number before initiating the callback, and in some embodiments a voice synthesizer is provided to speak the callback number to the user. In still other embodiments the pager of the invention is configured to receive, store, and playback alphanumeric messages combined with the ability to auto-dial calls with the DTMF generation elements.

Brief Description of the Drawing Figures

Fig. 1A is a front view of a dialing pager according to an embodiment of the present invention.

Fig. IB is a diagram of internal elements of the dialing pager of Fig. 1A.

Fig. 2A is a front view of a dialing pager according to an alternative embodiment of the present invention.

Fig. 2B is a diagram of internal elements of the dialing pager of Fig. 2A.

Fig. 3A is a front view of a dialing pager according to another alternative embodiment of the present invention.

Fig. 3B is a diagram of internal elements of the dialing pager of Fig. 3A.

Fig. 4A is a front view of yet another alternative embodiment of the present invention.

Fig. 4B is a diagram of internal elements of the dialing pager of Fig. 4A.

Description of the Preferred Embodiments

Dual Tone Multi-Frequency (DTMF) audio signals are used in state-of-the-art telephone systems for activating switching equipment to route telephone calls. Touchtone key pads on a standard pushbutton telephone activate DTMF signals that dial telephone numbers. (Touchtone is trademarked by the American Telephone and Telegraph Company). There are twelve key pads corresponding to the digits 0 through 9, the star symbol (*), and the pound symbol (#). Some telephones and specialized electronic devices have four additional keys, designated A, B, C, and D.

The DTMF system of touchtone dialing uses internationally standardized combinations of frequencies.

Table 1 is a matrix showing the high and low frequency pair, in Hz, required for each of the 16 characters in a full key pad configuration. Each character from the touchtone keypad is represented by a dual set of audio frequency signals, which when transmitted together are recognized by other electronic equipment as the unique representation of the keypad character.

Lower Frequency j Higher Frequency (Hz)

(Hz) ! 1209 1336 1447 1633

697 1 1 2 3 A A

770 4 5 6 B

852 7 8 9 C

941 * 0 # D

TABLE 1

Low-cost voice synthesizers on microminiaturized integrated circuit chips are rapidly giving machines the ability to speak. In its simplest form, voice synthesis is based on "concatenation," a juxtaposition of stored signals for each vocabulary item. The "digitized voice" synthesis system stores the concatenated human utterances of desired words or phrases. The digitized voice system works fine for numbers and a few pat phrases.

Other methods with less memory storage requirements are "parameterized synthesis," which extracts informative parameters from the original human speech and later reconstructs speech from the stored parameters, and "phonemic synthesis," which abstractly represents each word as a sequence of expected vowels and consonants (phonemes). The newer "text-to-speech" synthesizers generate large vocabularies of speech from computerized text instead of the human voice and have minimal memory requirements.

Memory requirements are also reduced by efficient speech encoding methods such as the Mozer time-domain method, which divides speech into short analysis periods so the important features within the waveform of each period can be defined and stored as a minimal representation. The refinements in synthesizer technology have made possible its use in many electronic devices today. The present invention, referred to herein as a "dialing pager," provides a tonal-type pager to receive calls from an unlimited number of parties and to automatically dial return calls without requiring a physical signal connection between pager and telephone equipment.

Fig. 1A is a front view of a dialing pager 11 according to an embodiment of the present invention. The

dialing pager device in this embodiment is miniaturized, approximately the size of a wristwatch, but could vary in other embodiments in shape and size dependent on marketing applications. External elements include a pager on/off switch 15, a call replay button 19, a speaker 21, and a speaker volume control dial 17. In some embodiments a buzzer is incorporated as a signal element to alert a user that a page has been received. The internal elements in this embodiment are diagrammed in Fig. IB. They include, but are not limited to, an antenna 12 for receiving radio signals, a demodulator 14 for converting the incoming radio signal to a digital representation, central processing unit (CPU) 16, random access memory (RAM) 18, and a tonal generator 20, configured to operate a speaker 21 to produce audible DTMF signals. The digital units communicate on an internal bus 22, and coin cell battery (not shown) powers the device. In addition, the buzzer if one is used, on-off switch, replay button, and volume control are not shown in the diagram, but are connected to the other internal elements in a conventional manner.

When a call is received the radio signal is demodulated by demodulator 14 and the CPU, guided by control routines, causes a beep signal to be issued from the speaker, or an alternative buzzer to operate, to alert the user to the receipt of a call. The user, to make the callback, holds the pager so speaker 21 is proximate a telephone receiver 23, and keys replay button 19. The CPU in response activates generator 20 to output DTMF signals corresponding to the number to be called through speaker 21. The DTMF signals are the same as those produced from a standard twelve-button touch-tone telephone key pad (see description under "Background of the Invention").

This unique and innovative use of the DTMF feature provides "on-the-road" pager users with a automated dial capability to conveniently call back from any telephone

connected to DTMF activated switching equipment.

Fig. 2A is a front view of an alternative embodiment 25 of a dialing pager similar to the tonal-only pager described in Fig. 1A, comprising additionally a voice synthesizer to "speak" the callback number to the user. Alternatively the unit may be configured to relate the callback telephone number to a caller's name, and speak the caller's name instead of the number. The Fig. 2A embodiment allows the user to select between tonal and voice modes of output. The tonal mode produces DTMF signals as its output and comprises an on-off switch 29, a volume control 31, a replay button 33, and a speaker 34. There is additionally a selector 35 to choose between DTMF and voice output. The voice mode announces the calling number or the caller's name with a human-sounding, synthesized voice.

The tonal and voice modes use the same speaker 34. The internal elements of this embodiment, diagrammed in Fig. 2B, comprise an antenna 36, a demodulator 37, a CPU 39, RAM 41, a DTMF generator 43, a bus structure 45 and a speech synthesizer section 47. The synthesizer section comprises in this embodiment a digital-to analog converter, low-pass filter, synthesizer algorithms and read-only memory to store synthesis data, all of which is conventional to speech synthesis, and not shown in Fig. 2B. Any of the human voice-based synthesizer systems, "digitized voice," or "parameterized," or "phonemic," are suitable for this embodiment. In addition, the on-off switch, replay button, volume control, and voice/DTMF selector are not shown in the diagram, but are connected to the other internal elements in a conventional manner.

Fig. 3A shows yet another embodiment 49 of the invention having an LCD display 51 to provide the user with a visual interface as well as DTMF dialing capability. Other external elements in the embodiment of

Fig. 3A comprise on-off selector 55, volume control 57, replay button 59, and speaker 60. The internal elements in this embodiment are diagrammed in Fig. 3B, and comprise an antenna 61, a demodulator 63, a CPU 65, RAM 67, DTMF generator 69, and bus structure 71. There is additionally a display driver 73, which outputs to display 51. In addition, the on-off switch, replay button, and volume control are not shown in the diagram, but are connected to the other internal elements in a conventional manner. This embodiment provides all the features of a conventional pager plus the ability to dial the phone without a direct physical connection.

Fig. 4A shows yet another embodiment 75 integrating tonal and voice synthesis features and an LCD display. In this embodiment the external elements comprise display 79, on-off selector 81, volume control 83, DTMF/voice output selector 85, speaker 87, and replay button 89. This embodiment provides an automated dialing capability and the means to identify the caller through an optional synthesized voice message and visually on the LCD display.

Fig. 4B diagrams the internal elements of this embodiment, which comprise antenna 91, demodulator 93, CPU 95, RAM 97, DTMF generator 99, voice synthesizer 101, display driver 103 for driving display 79, and bus structure 105. In addition, the on-off switch, volume control, DTMF/voice selector, and replay button are not shown in the diagram, but are connected to the other internal elements in a conventional manner.

In other embodiments not shown in detail in the drawings alphanumeric data may be received, stored, recalled, and displayed, whereby a user may receive messages, combined with the ability to switch phone dialing equipment with DTMF signals. For message capability a somewhat larger display and additional control routines are required.

It will be apparent to one skilled in the art that there are a relatively large number of changes that may be made in the embodiments described without departing from the spirit and scope of the present invention. Some additions and alternates have been mentioned above. For example, provisions have been made to add an voice synthesizer option to the dialing pager. Another variation adds an LCD display to the dialing pager while another combines an LCD display and voice synthesizer option with the dialing pager. There are also alternative means available for alerting a user that a page has been received, such as buzzer or vibrator (tactile alert), or a tone from the speaker, and these features may be embodied in other embodiments of the invention.

There are a number of equivalent ways the several features might be implemented without departing from the spirit and scope of the invention as well. There are, for example, several choices among speech synthesis elements, as there are among speakers, LEDs or lights if these are to be used as alerting elements, types of switches and volume controls, and so on. There are many sorts of cases that might be used. Different embodiments can be rendered in different sizes. There are many other deviations that all fall within the spirit and scope of the invention.