WO1993010618A1

WO1993010618A1 - Mobile telephone system for receiving and storing alpha-numeric information

Info

Publication number: WO1993010618A1
Application number: PCT/US1992/009779
Authority: WO
Inventors: Martin Alpert
Original assignee: Cumulus Corporation
Priority date: 1991-11-19
Filing date: 1992-11-19
Publication date: 1993-05-27
Also published as: AU3134593A

Abstract

A cellular telephone (11) is provided for transmitting a modulated radio frequency signal with alpha-numeric information encoded thereon, and a mobile telephone (10) for receiving and storing the information, such telephone including means for receiving the radio frequency signal, means for detecting and decoding the alpha-numeric information on the carrier, means for storing the alpha-numeric information in memory in the telephone, and means for retrieving the stored information, even during a telephone conversation. According to another aspect of the invention, a mobile telephone for receiving and storing alpha-numeric information is provided, such telephone comprises means for receiving a modulated radio frequency carrier signal having alpha-numeric information encoded thereon, means for storing such alpha-numeric information in memory in the telephone, and means for retrieving the stored information.

Description

TITLE: MOBILE TELEPHONE SYSTEM FOR RECEIVING AND

STORING ALPHA-NUMERIC INFORMATION

TECHNICAL FIELD OF THE INVENTION 5 The present invention relates to radio communication systems in general, and in particular, to two-way mobile telephone systems. Even more particularly, the present

invention relates to a cellular mobile telephone system for receiving and storing alpha¬ x numeric information within a cellular telephone.

BACKGROUND OF THE INVENTION

10 Cellular mobile telephone systems are known in the art. Cellular mobile telephone systems provide cellular telephone users with increased mobility and/or accessibility for making and receiving telephone calls as compared to the standard telephone system. A cellular telephone system allows users travelling in their automobiles, walking about, etc., to make and receive telephone calls even without necessarily having access to a standard

15 telephone.

A cellular telephone for use in the system typically includes a handset and radio transceiver. The handset includes a mouthpiece and an earpiece similar to a standard telephone. The handset is connected to the transceiver with electrical cable, and the handset also includes a display and a keypad that enables the cellular telephone user to enter

20 a telephone number to be called by depressing the appropriate keys or buttons. In addition, the keypad may include one or more special function keys which activate certain features such as, for example, hands-free calling or placing a party on hold.

As with a standard telephone, to place a call using the cellular telephone, the cellular telephone user simply picks up the handset in his or her automobile, carry bag, etc. and

25 dials the telephone number of the desired party. To receive a call using the cellular telephone, the cellular telephone user responds by picking up the handset or pressing an "answer" function key upon receiving notification that an incoming call has arrived.

It is also known in the art that cellular mobile telephone systems are configured so as to include a grid of small service zones, referred to as "cells", which cover a particular

30 geographic region. It is only within the geographic region that calls can be made or received by the cellular telephone. Such cellular telephone systems rely on a network of radio signal transmission stations positioned within the cells to maintain a connection with the cellular telephone. More specifically, at one or more cell sites within each cell, there is a low-power if transmission station which serves as the radio link between the cellular telephone transceiver and the rest of the cellular telephone system network. Each rf transmission station is linked to a central control station of the cellular telephone system. The central control station in turn is connected to the standard local telephone network. As a result, the cellular telephone user is able to connect into the local telephone network and to make and to receive telephone calls just as if the user were calling from a standard

telephone.

Accordingly, when a call is placed to the cellular telephone user, the call is routed through the standard telephone system to the central control station. From the central control station, the call is directed by way of a land-line trunk to the rf transmission station generally nearest the cellular telephone user. The call is broadcast from the rf transmission station on an rf carrier and is received in the radio transceiver in the cellular telephone. When making a call, the cellular telephone user enters the number of the party to be called by pressing the appropriate digit keys (and possibly a "send" function key) on the handset as is noted above. In turn, the cellular telephone transceiver establishes a two-way radio communication link with the appropriate rf transmission station servicing the cell. The rf transmission station receives the necessary control and destination information from the cellular telephone, and from the transmission station the call is routed through the land-line trunk and the central control station into the standard telephone network. Thereby, two- way communication is established between the cellular telephone user and the called party. There are several known methods for handing off control of the cellular telephone signal as the user moves from cell to cell. Primarily, the system logic determines which rf transmission station in which cell is utilized for establishing and maintaining communications with the user during a telephone call. The result is that the cellular telephone user is provided with additional mobility and/or accessibility as compared to a conventional telephone.

Unfortunately, there have been several drawbacks associated with cellular telephones and telephone systems in the past. One particular drawback has been that previous cellular telephones have been designed for exchanging primarily only analog voice communications. Cellular telephones in the past have been limited in their ability to transmit and receive digital data and/or alpha-numeric information. (The terms "digital data" and "alpha¬ numeric information" may be used equivalently and interchanged below.) Such cellular telephones were quite capable of allowing conventional voice conversation over the telephone. However, the exchange of other types of information was limited primarily to the transfer of control data within the cellular system. This control data served to maintain the communication link between the cellular telephone and the local telephone network.

Thus, cellular telephones in the past have not been capable of receiving and storing information that users may find to be useful, such as alpha-numeric information. For example, oftentimes a situation will arise where a party speaking with the cellular telephone user wants to convey important information such as a telephone number, an address, a flight itinerary, etc., to the user. However, the user cannot take the time to write the information on a notepad because, for example, the cellular telephone user is driving an automobile while conversing over the telephone. The cellular telephone user would be taking an undesirable risk if the user were to divert his or her attention from the road in order to write down the information. Because cellular telephones in the past were not suited to receive and store such alpha-numeric information for subsequent retrieval by the user, the user might risk an accident by diverting attention from the road to a notepad.

As another example, the cellular telephone user may not have writing materials at his or her disposal with which to write information such as a telephone number, street address, etc. Previous cellular telephones have not been suitable for receiving and storing the information as a type of electronic notepad. As a result, such information might have been forgotten by the user shortly after the conversation had concluded.

Still another drawback has been that previous cellular telephones, when left unattended, have not been able to receive and store information such as an alpha-numeric message for subsequent retrieval by the user. Such message could consist of information regarding a business meeting, scheduling information, a telephone number to call, etc.

Although there have been previous attempts at receiving and storing alpha-numeric information for use with a cellular telephone, such attempts have required the use of expensive peripheral equipment. Unlike the present invention, such previous attempts did not provide a mobile cellular telephone system and method in which alpha-numeric information could be received and stored within the cellular telephone itself for subsequent retrieval by the user. Instead, the cellular telephone and system relied on additional peripheral equipment to perform such function. For example, described in United States Patent Nos. 4,747,122, 4,860,335 and

4,661,972 are systems in which a cellular telephone is used in conjunction with peripheral equipment to receive an incoming call and to store a telephone number input by the caller. However, such systems require the use of a radio paging system or an automotive anti-theft system in conjunction with the cellular telephone.

Li view of the various shortcoming associated with cellular telephone systems in the past, there is a strong need in the art for a cellular telephone system and method which provides for the receipt and storage of alpha-numeric information (or digital data).

Moreover, there is a strong need for a cellular telephone which can receive and store such information for subsequent retrieval by the user, even while a conversation is occurring over the cellular telephone.

In addition, there is a strong need in the art for a cellular telephone which is capable of receiving and storing multiple messages for subsequent retrieval by the cellular telephone user. There also is a strong need in the art for a cellular telephone which can automatically dial telephone numbers which may be stored as a message.

Accordingly, the present invention overcomes the aforementioned shortcomings of the above-known and similar cellular telephones and systems. The present invention provides an improved system and technique for sending, receiving and storing alpha¬ numeric information in a cellular telephone. The present invention is summarized and described in detail below.

SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a cellular telephone system in which alpha-numeric information can be .sent to and received by a cellular telephone. The information is stored in memory in the cellular telephone such that the cellular telephone user is able to retrieve the information.

The information is encoded and transmitted to the cellular telephone using a variety of methods. For example, the alpha-numeric information may be encoded and transmitted using a conventional touch-tone keypad. Alternatively, the alpha-numeric information may be encoded and transmitted using a personal computer.

In its preferred embodiment, the present invention allows a person engaged in a call with a cellular telephone user to transmit alpha-numeric information to the cellular telephone where it is stored in memory within the cellular telephone. When the cellular telephone user chooses to do so, the user can retrieve the information from the memory. Moreover, the present invention permits multiple alpha-numeric messages to be stored in the cellular telephone. The alpha-numeric messages may be received and stored while the telephone is not in use and even while a conversation is occurring. In the event the alpha-numeric message is a telephone number, the telephone number is stored in the cellular telephone, and the user can elect to have the cellular telephone automatically dial the telephone number. The present invention also provides a cellular telephone system in which the cellular telephone has a dedicated I/O connector for use with a modem, facsimile, headset, etc. In addition, the present invention offers a cellular telephone which includes a digital voice mailbox wherein a party calling the cellular telephone may leave a digitized message. Subsequently, the digitized message can be retrieved from memory by the cellular telephone user.

According to one particular aspect of the present invention, a cellular telephone is provided which includes means for transmitting a modulated radio frequency signal with alpha-numeric information encoded thereon, and a mobile telephone for receiving and storing the information, such telephone including means for receiving the radio frequency signal, means for detecting and decoding the alpha-numeric information on the carrier, means for storing the alpha-numeric information in memory in the telephone, and means for retrieving the stored information, even during a telephone conversation.

According to another aspect of the invention, a mobile telephone for receiving and storing alpha-numeric information is provided, such telephone comprises means for receiving a modulated radio frequency carrier signal having alpha-numeric information encoded thereon, means for detecting and decoding such alpha-numeric information on the carrier, means for storing such alpha-numeric information in memory in the telephone, and means for retrieving the stored information.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but only a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

In the annexed drawings: Fig. 1 is a system diagram of a cellular mobile telephone system which embodies the principles of the present invention; Fig. 2 is a block diagram of a cellular telephone used in the system of Fig. 1 in accordance with the present invention;

Fig. 3 is a detailed block diagram of the cellular telephone shown in Fig. 2; Fig. 4A is a flow chart showing one embodiment of the system logic associated with receiving and storing a telephone number in accordance with the cellular telephone of the present invention;

Fig. 4B is a timing diagram showing encoded alpha-numeric information representing a telephone number to be received by the cellular telephone of the present invention in accordance with the principles exemplified in the flow chart of Fig. 4A; Fig. 5A is a flow chart showing another embodiment of the system logic associated with receiving and storing a telephone number using the cellular telephone of the present invention;

Fig. 5B is a timing diagram showing encoded alpha-numeric information representing a telephone number to be received by the cellular telephone of the present invention in accordance with the system logic shown in the flow chart of Fig. 5A;

Fig. 6A is a flow chart showing an embodiment of the system logic associated with receiving and storing an alpha-numeric message when using a cellular telephone in accordance with the present invention;

Fig. 6B is a timing diagram showing encoded alpha-numeric information comprising a message for receipt and storage in accordance with the flow chart of Fig. 6A;

Fig. 7 is a flow chart showing the system logic for recording a message in accordance with the present invention;

Fig. 8 is a schematic diagram of a modem to cellular interface in accordance with the present invention; Figs. 9 and 10 are flow charts showing the system logic for placing and receiving, respectively, a call through a modem or facsimile machine in accordance with the present invention; and

Fig. 11 is a detailed schematic diagram of the digital and audio portion of the cellular telephone of Fig. 3 in accordance with the present invention. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now to the drawings, wherein like numerals are used to refer to like elements throughout, a cellular mobile telephone system 10 in accordance with the present invention is shown in Fig. 1. The cellular mobile telephone system 10 includes at least one cellular telephone 11 (shown schematically enlarged) which is typically, although not necessarily, installed in an automobile 12, truck, boat, etc. Alternatively, the cellular telephone may be a portable device which is carried by the user.

The cellular telephone 11 operates within a predefined geographic region 14 which consists of a number of individual cells 16 of the cellular telephone system 10. Each cell 16 includes one or more low-power rf transmission stations 18 which are positioned at predetermined cell sites within each cell. As is described above, the rf transmission stations 18 provide the radio link to the cellular telephone when the user is in the corresponding cell. As a result, the cellular telephone user is provided with access to the standard local telephone network 20 in the region 14.

Specifically, the cellular telephone system 10 is configured so that the rf transmission stations 18 are connected to a cellular telephone central control station 22 using trunks 24. The central control station 22 is linked to the local telephone network 20 through trunk 28. Thus, the cellular telephone system 10 permits the cellular telephone user to establish and conduct from anywhere within the region 14 a two-way communication link with another telephone 30 at the opposite end 32 of the local telephone network 20.

The system control of the cellular telephone system 10 uses any of several known methods to carry out the control and routing of telephone calls involving the cellular telephone in the automobile 12. Even as the automobile travels from cell to cell 16, the system 10 hands-off control of the telephone call amongst the appropriate rf transmission stations 18.

Using known techniques, during a cellular telephone call, radio communication between the transceiver of the cellular telephone 11 and the respective rf transmission station 18 occurs over full duplex rf channels. The call is set up initially between the cellular telephone and the respective rf transmission station 18 using one out of a number of dedicated control channels available in the system 10. After the call is initialized, a duplex voice connection using a pair of voice channels is established. Thereafter, any further transmission of system control information occurs over the voice channels by blanking out the audio and transmitting the control data for a brief instant. Accordingly, the cellular telephone 11 and telephone system 10 of the present invention operate in a conventional manner to the extent that the telephone receives voice and system 10 control data over the voice channels.

However, the cellular telephone system 10 of the present invention also permits the sending, receiving, and storage of alpha-numeric information transmitted from the opposite end 32 of the local telephone network 20. In the preferred embodiment, the alpha-numeric information is encoded as a series of dual-tone multifrequency (DTMF) tones generated by the telephone 30 at the opposite end 32. Alternatively, such information may consist of a series of DTMF tones generated by a personal computer 34 and/or modem 36.

In view of the disclosure herein, it will be apparent to those having ordinary skill in the art that there are a variety of methods for generating DTMF tones or for otherwise encoding alpha-numeric information for use in the present invention. Thus, while the preferred embodiment is discussed in the context of DTMF tones, other known methods are well within the intended scope of the present invention.

The DTMF tones are transmitted through the local telephone network 20 and are received at the central control station 22 through trunk 28. Together with any voice communication from the caller at end 32, the DTMF tones are routed from the control station 22 through the trunk 24 to the rf transmission station 18 in the appropriate cell 16. From the rf transmission station 18, the DTMF tones along with any voice communication are broadcast on an rf carrier such that they can be received and decoded by the cellular telephone 11 in the automobile 12, carry bag, etc.

As is noted above, the cellular telephone 11 of the present invention receives the alpha-numeric information encoded in the DTMF tones even while a conversation is occurring. Therefore, it is not necessary to interrupt a conversation in order to permit the transfer and receipt of the alpha-numeric message. Moreover, the cellular telephone 11 of the present invention can receive and store alpha-numeric information even though the cellular telephone user is unavailable. By simply leaving the telephone in the "on-hook" mode, the cellular telephone will answer a call automatically and will proceed to receive and store the alpha-numeric information, as is explained in detail below. Thus, a caller may leave a message with the cellular telephone user without requiring the cellular telephone user to be present to receive the call. Referring now to Fig. 2, a block diagram of a cellular telephone 50 (designated 11 in Fig. 1) according to the preferred embodiment of the present invention is shown. The cellular telephone 50 consists primarily of two portions, the handset 52 and the transceiver 54. The handset 52 and the transceiver 54 may be separate from each other and joined by electrical cables, or the handset 52 and the transceiver may be combined in a single enclosure to form an integral unit. As is shown, the handset 52 includes an earpiece 56, microphone 58, display 60 and keypad 62.

The transceiver 54 includes a cellular telephone control unit 64 and a DTMF receiver 66 for receiving and decoding the DTMF tones. The control unit 64 serves as the primary controller for the circuitry in the cellular telephone 50. The control unit 64 can be a microcontroller or a microprocessor, as will be appreciated, and the operating code and system program (also referred to herein as the software program) can be stored in the control unit internal memory and/or external memory, as described further below. The system program as referred to herein embodies conventional system programming techniques utilized in existing cellular telephones. Furthermore, the system program includes a number of modifications over existing system programs for implementing the procedures described herein and illustrated in the drawings. All such modifications will be apparent to those having ordinary skill in the art of programming in view of the following disclosure. The transceiver 54 includes an rf circuit 68 which, in combination with an antenna

70, serves to provide the radio communication link between the cellular telephone 50 and the respective rf transmission station 18. The cellular telephone transceiver 54 also contains an audio and digital signal processor 72 for performing the necessary processing of the audio and digital signals between the control unit 64 and the rf circuit 68. In addition, the transceiver 54 includes memory 74 for storing alpha-numeric information received by the cellular telephone 50. If desired, the memory 74 also may be used to store the system program, as is mentioned above. A solid state voice recorder 75 is included in the transceiver 54 for recording and playing back voice messages.

As is shown in Fig. 2, the inputs of the DTMF receiver 66, audio and data processor 72, and recorder 75 are each connected to the receive audio path 76 from the audio output 77 of the rf circuit 68. Upon recognizing a valid DTMF tone on the receive audio path 76, the DTMF receiver 66 notifies the control unit 64 of the presence of a DTMF tone by way of control line 78. In addition, the DTMF receiver 66 proceeds to decode the DTMF tone and provides to the control unit 64 a digital data signal on data line 80 representing the numeric value of the decoded tone. After receiving a DTMF tone, the DTMF receiver 66 looks for the absence of a

DTMF tone for a predetermined amount of time, as is described below. In the event that an additional DTMF tone is not received within such predetermined time, the DTMF receiver 66 concludes that a valid gap requirement between DTMF individual tones has been met and prepares for the reception and decoding of the next DTMF tone which is provided to the control unit 64 via line 80. In such manner, the DTMF receiver 66 provides the control unit 64 with a digital data sequence representing numeric values which correspond to the DTMF tones which were decoded from the audio receive path 76 in the transceiver 54.

The control unit 64 causes the decoded information to be stored in the memory 74 for subsequent retrieval. In addition, in the preferred embodiment the control unit 64 causes the alpha-numeric information received from the DTMF receiver 66 to be displayed on the display 60 via line 81. Thus, the alpha-numeric information received by the cellular telephone can be viewed by the cellular telephone user as the information is received and/or after the information is stored in memory 74 for use by the cellular telephone user at another time.

To initiate a call using the cellular telephone shown in Fig. 2, the user enters the desired telephone number into the control unit 64 via line 82 using the keypad 62. In the preferred embodiment, the telephone number is simultaneously displayed on the display 60 as the telephone number is entered. In turn, the control unit 64 operates as is conventional to provide the various output and control signals to the audio and data processor 72 by way of control/data line 83. The microphone 58 provides the audio input signal along line 84 to the audio and data processor 72. The output 85 of the audio and data processor 72 provides the modulation input along line 86 to the rf circuit 68, and the modulated radio signal is broadcast to the rf transmission station 18 by way of the antenna 70. Incoming cellular communications received by the antenna 70 are demodulated by the rf circuit 68 in a conventional manner such that the audio output 77 provides the demodulated audio signal on the receive audio path 76. Voice information and system 10 control data found on the receive audio path 76 is processed in the audio and data processor 72 as is conventional. The audio and data processor 72 in turn provides the voice information to the earpiece 56 along line 87. The system control information on the receive audio path 76 is provided via line 83 to the control unit 64 for further processing, as is described in detail below.

Referring now to Fig. 3, a detailed block diagram of the cellular telephone 50 in accordance with the present invention is shown. In the preferred embodiment, the rf circuit 68 includes a receiver 90, transmitter 92, and duplex filter 94. The audio and data processor 72 incorporates a data processor 96 and audio processors 98 and 100. The memory 74 includes, for example, read-only-memory (ROM) 102, latch 104, and random- access-memory (RAM) 106. In addition, the cellular telephone 50 includes a power supply 108.

The control unit 64 is a microcontroller integrated circuit such as the commercially available S80C552 8-bit microcontroller manufactured by Signetics Corp. As is shown in Fig. 3, the control unit 64 is one of several components which share a bi-directional data line 110. The control unit 64 also shares an address/data bus 112 with the memory 74. The requisite digital data and control information is communicated between the various components within the transceiver 54 and handset 52 primarily by way of the bi-directional data line 110 and the address/data bus 112.

Other control or data lines include a transmit control line 114 between the control unit 64 and the transmitter 92 which provides the signal which enables the transmitter 92. Furthermore, pulse width modulation line 116 provides the appropriate pulse width modulation control information from the control unit 64 to the transmitter 92. Line 118 delivers analog control information from the receiver 90 to the A/D converter input 119 of the control unit 64 where it is subsequently processed.

With respect to the DTMF receiver 66, the preferred embodiment of the present invention includes a four-bit DTMF receiver integrated circuit that is capable of decoding sixteen different DTMF tones. The DTMF receiver 66 preferably provides a four bit output code representative of the detected DTMF tone as received at the input of the DTMF receiver 66. One exemplary DTMF receiver suitable for use in the cellular telephone 50 of the present invention is the commercially available SSI 75T204 integrated circuit manufactured by Silicon Systems, Inc.

The data processor 96 in the cellular telephone 50 is configured as is conventional to perform the data transceiving, data processing, and supervisory audio tone functions required in the cellular telephone for use in a particular cellular system 10. One such data processor 96 is the commercially available UMAIOOO integrated circuit manufactured by Signetics. The audio processors 98 and 100 provide the audio processing of the signal received from the audio receive path 76 as described above. Two processors which may be utilized as audio processors 98 and 100 are integrated circuits NE/SA5751 and NE/SA5750, respectively, which are commercially manufactured by Signetics.

The receiver 90, transmitter 92 and duplex filter 94 in the rf circuit 68 may be any of several commercially available components known in the art to be suitable for use in a cellular telephone system. The memory 74 is any of several commercially available memory chips, and the handset 52 consists of off-the-shelf components as does the power supply 108.

The flow chart shown in Fig. 4A illustrates one embodiment of a computer program or system logic for operation of the cellular telephone 50 for receiving and storing alpha¬ numeric information which represents a telephone number. Shown in Fig. 4B is typical sequence 130 of DTMF tones which represent a telephone number which may be decoded and stored in accordance with the system logic shown in Fig. 4A. The sequence 130 is a series of tone bursts, each of which represents one of the standard DTMF digits. As is noted above, this sequence 130 can be generated manually by way of the key pad on the telephone 30 at the opposite end 32 of the cellular telephone system link. Alternatively, the sequence 130 can be generated by the computer 34 and modem 36, a touch-tone generator board with appropriate software, etc.

The DTMF receiver 66 and the control unit 64 combine to receive and store the alpha-numeric information in the sequence 130 in accordance with the steps shown in Fig.

4A. In order to implement the procedure shown in Fig. 4A, the control unit 64 is programmed using known programming techniques to perform the steps shown in Fig. 4A using the various commands in the control unit instruction set. As with the other system flow charts and program control logic included and discussed herein, those having ordinary skill in the art will be able to easily write such programs in view of the disclosure.

Beginning in step 132, the cellular telephone 50 is initialized as shown by line 133 by an asynchronous event such as when the telephone is powered up, a special function key on the handset is pressed, or otherwise is placed in a standby mode. In step 132, the cellular telephone 50 waits receive alpha-numeric information representing a telephone number or the like. The flag STOREFLAG is set to "0" to indicate in the microprocessor portion of the control unit 64 that the cellular telephone 50 is ready to receive a new sequence 130 of alpha-numeric information. In step 134, the control unit 64 determines from the logic level on the control line 78 whether the DTMF receiver 66 has received and decoded a DTMF tone from the audio receive path 76. If the DTMF receiver 66 has received a tone, the control unit 64 samples the output of the DTMF receiver 66 at lines 80 and determines whether the decoded numeric digit is within the range of 0-9.

In the event an alpha-numeric digit in the range of 0-9 is detected in step 136, the control unit 64 in step 138 sets the STOREFLAG to "1" to indicate receipt of an alpha¬ numeric digit. Furthermore, the control unit 64 causes the decoded alpha-numeric digit to be stored in the RAM memory 106 via address/data bus 112, and then control is returned to step 134 to await the arrival of the next DTMF tone. Thus, based on the exemplary alpha-numeric sequence 130 shown in Fig. 4B, the numbers corresponding to the telephone number 555-1212 will be received and stored in the memory 106.

At step 136, if the detected DTMF tone is not an alpha-numeric digit in the range of 0-9, the control unit 64 proceeds to step 140 where it determines whether the detected tone represents an end of data (EOD) marker code. The EOD marker in the sequence 130 consists of the DTMF tone burst which represents the "*" on a conventional key pad (sometimes referred to below as the tone bursts "*"). However, a different or more complex EOD marker code certainly is contemplated as being within the intended scope of the present invention.

If the EOD marker code is detected at step 140, the control unit 64 determines whether the flag STOREFLAG already has been set to "1", thereby indicating the receipt of a valid numeric data sequence 130 as is shown in step 142. In the event the STOREFLAG is set to "1", the control unit 64 proceeds to store the received numerical data in an appropriate location in RAM 106. Thus, in step 144, the control unit 64 places the information at a particular address in RAM 106. The control unit 64 then increments the pointer in the central processing unit for the control unit 64 to point to the storage area for the next numeric sequence 130 to be received. Upon receipt of the alpha-numeric information representing a telephone number, the control unit 64 can be programmed in a conventional way to cause the alpha-numeric sequence 130 to be displayed on display 60 by way of the data line 110. If multiple sequences 130 have been received and are stored in memory, the control unit can be programmed using conventional programming techniques to display the stored information in a variety of ways, including displaying the last number received, or permitting the user to scan through the stored information by pressing the appropriate special function keys on the keyboard 62. As referred to herein, special function keys or sequences of keys on the handset can be used to achieve a prescribed action, e.g., scrolling of memory data, replay of a message, etc. The pressing of such key(s) causes an interrupt to the control unit 64 which in conventional programmed fashion carries out the desired function.

Referring now to step 140, if a DTMF tone is detected which is not representative of a valid alpha-numeric digit or an EOD marker code, an error signal is produced within the control unit 64, as is shown in step 146. Preferably, an error display is generated by the control unit 64 and an error signal is indicated on the handset 52 using the display 60. In addition, or as an alternative, a warning signal may be provided over the earpiece 56. Likewise, in step 142, if an EOD marker code is received before the receipt of valid numeric data as indicated by the flag STOREFLAG being previously set to "1", an error signal is implemented by the control unit 64 as is shown in step 148.

In the event an error occurs in the cellular telephone 50, the system returns to step 132 and the control unit 64 causes the DTMF receiver 66 and the flag STOREFLAG to be reset. Thus, after an error occurs, the telephone 50 again will be ready to receive additional information.

After an alpha-numeric sequence 130 representing a telephone number is received by the cellular telephone 50 and stored in memory, the cellular telephone user is able simply to press a "recall" special function key on the keypad 64 to cause the cellular telephone 50 to call the stored telephone number automatically. The "recall" function key produces a signal on data line 110 which instructs the control unit 64 to retrieve the telephone number stored in RAM 106. The control unit 64 loads the stored telephone number into a shift register or the like for dialing in the same manner as if the telephone number were are input directly from the key pad 62. The control unit then initiates the "send" function, and the stored telephone number is dialed.

In the event multiple telephone numbers are received and stored as noted above, the program for the control unit 64 enables the multiple telephone numbers stored in memory to be retrieved from the memory "stack" using conventional routines. For example, the control unit 64 may be programmed to retrieve the stored numbers using a first in, first out basis; using a last in, first out basis; or the control unit may permit the cellular telephone user to scan through the stored numbers by way of one or more special function keys on keypad 62 used in conjunction with display 60 on the handset 52. By depressing the

"recall" key, the cellular telephone 50 dials the selected stored number, as described above.

An alternate embodiment of the system logic and method of operation for receiving and storing alpha-numerical information is illustrated in Fig. 5A. In such an embodiment, both an EOD marker code and a start-of-data (SOD) marker code are used for the transmission and receipt of an alpha-numeric sequence 155 (Fig. 5B) which again represents a telephone number.

The telephone 50 is set in an idle or stand-by mode which is programmed to occur, for example, with the occurrence of an asynchronous event as represented by line 133 such as power applied to the telephone 50, a special function key being depressed, etc. In the stand-by mode of step 157, the telephone 50 awaits the receipt of numeric values representative of a new alpha-numeric sequence 155 from the output of the DTMF receiver 66. In the idle or standby mode, the flag STOREFLAG is set to "0". The control unit 64 then waits for an indication from the DTMF receiver 66 that a DTMF tone has been detected, as is shown in step 159. When a DTMF tone is detected, the system within the cellular telephone 50 determines in step 161 whether the received tone is an SOD marker code such as a DTMF tone burst representing "*" in this case. If so, the control unit 64 initializes itself in step 163 to prepare to receive incoming alpha-numeric information. If a DTMF tone other than an SOD marker code is received in step 161, an error signal is reported in step 164 in the same way as is described above. After the control unit 64 has been initialized to receive the telephone numbering step 163, the control unit 64 monitors the output of the DTMF receiver 66 until a succeeding DTMF tone is detected as is shown in step 166. In step 168, the control unit 64 determines whether the decoded DTMF tone is a valid alpha-numeric digit within the range 0-9. If so, the flag STOREFLAG is set to "1" in step 170, and the numeric digit is stored by the control unit 64 in RAM 106.

If the decoded DTMF tone detected in step 166 represents something other than an alpha-numeric digit in the range of 0-9, the control unit 64 in step 172 determines whether a valid EOD marker code has been received which signals the end of particular alpha- numeric sequence 155. If so, the control unit in step 174 checks to make sure that the flag

STOREFLAG previously has been set to "1" indicating that valid numeric information already has been received and stored. If the flag STOREFLAG has not been set to "1", an error report is made, as is shown in step 176. Otherwise, valid alpha-numeric information is stored at an appropriate location in RAM 106, and the address of the stored numeric sequence 155 is noted by the control unit 64. As is shown in step 178, the microprocessor pointer in the control unit 64 is incremented to point to the memory storage for receipt of the next numeric sequence 155. Thereafter, the control unit 64 returns to an idle mode in step 157.

As was mentioned above, the cellular telephone 50 is capable of receiving and storing alpha-numeric information even while a conversation is occurring over the telephone. Specifically, the audio receive path 76 shown in Fig. 2 provides the audio input to both the DTMF receiver 66 and the audio and data processor 72. If desired, the front end of the DTMF receiver 66 may include a filter which filters the audio signal on line 76 so that only those audio frequencies which are at the DTMF tones proceed past the front end of the DTMF receiver 66. Therefore, the DTMF receiver 66 will be protected against undesirable noise created by the conversation. Similarly, a filter at the front end of the audio and data processor 72 can be used to filter out any DTMF tones so as to eliminate the audible chatter on the earpiece 56 associated with the DTMF tones.

Alternatively, the audio signal on the audio receive path 76 is fed directly into the input of the DTMF receiver 66 and the audio and data processor 72 without using additional filters. In such an embodiment, the DTMF receiver 66 decodes only the DTMF tones and ignores any other signals on the audio receive path 76. Simultaneously, the audio signal on the audio receive path 76, including any DTMF tones, is processed through the audio and data processor 72 to the earpiece 56. As a result, the chatter associated with the short bursts of DTMF tones may be heard by the user but will be buried in the background so as not to interrupt the conversation. Alternatively, the earpiece 56 may include a filter designed to filter out the DTMF tones.

Referring now to Fig. 6A, the system logic for receiving and storing an alpha¬ numeric message using the cellular telephone 50 is illustrated. In the preferred embodiment, alpha-numeric messages are transmitted to the cellular telephone 50 as a series of DTMF tones which form an alpha-numeric sequence 198 as exemplified in Fig. 6B. The alpha-numeric sequence 198 is generated at the transmitting end 32 using an encoding scheme in which the alpha-numeric characters A, B, C, etc. are encoded as a series of one or more DTMF tones. The cellular telephone 50 receives the alpha-numeric sequence 198 as described above and applies a reverse mapping routine to decode the DTMF tones into the appropriate characters. As one example, an encoding scheme may be utilized wherein a series of up to three consecutive identical DTMF tones representing one of the 0-9 numeric keys are used to represent one alpha-numeric character, as is described more fully below. In order to detect the end of a character and the beginning of the next character in sequence 198, the cellular telephone control unit 64 detects the presence of an end-of-character (EOC) marker code in the sequence 198. The EOC marker code may consist of, for example, the tone burst

II #11

When sending an alpha-numeric message to the cellular telephone 50, the numeric key "3" on telephone 30 creates a tone burst "3" which can be used by the sender to represent the characters "D", "E" and "F". A single tone burst "3" followed by an EOC marker code would represent the character "D". Two consecutive tone bursts "3" would represent the character "E"; three consecutive tone bursts "3" would represent the character "F"; and four consecutive tone bursts "3" followed by an EOC marker code would indicate the numeric character "3" itself.

A similar encoding procedure may be implemented using the remaining numeric keys on the telephone 30 key pad in order to provide a mapping function which includes the entire alphabet. Spaces between words in the alpha-numeric message may consist of a single tone burst "0". Other sequences of tone bursts may represent the other alpha¬ numeric characters such as "?", "!", ":", etc. As will be apparent to those having ordinary skill in the art in view of the disclosure, countless other mapping functions are equally suited and are within the intended scope of the present invention. Referring again to Fig. 6A, the system logic for receiving, decoding, and storing the alpha-numeric sequence 198 as exemplified in Fig. 6B is shown. The cellular telephone 50 again is in the stand-by mode initiated by line 133 as described above. In step 200, the control unit 64 searches for the occurrence of an SOD marker code from the output of the DTMF receiver 66. As is noted in the alpha-numeric sequence 198 shown in Fig. 6B, a series of two consecutive tone bursts "*" is used to indicate to the control unit 64 the start of data. The control unit 64 detects the SOD marker code using a sequence detecting algorithm which can be stored in ROM 102.

After the SOD marker code is received at the control unit 64, the control unit 64 initializes itself to receive alpha-numeric information represented by the sequence 198 of DTMF tones. In step 202, the control unit 64 determines whether a DTMF tone has been received by the DTMF receiver 66. When a DTMF tone is received, the control unit 64 determines whether the tone represents a valid numeric digit between 0-9, as is shown in step 204. If so, the control unit 64 causes the received numeric value to be stored in memory for subsequent decoding or mapping as noted in step 206. Thereafter, the control unit 64 returns to step 202.

If the next DTMF tone detected at step 202 does not represent a numeric digit between 0-9, the control unit 64 checks to see whether the DTMF tone is an EOC marker indicating the end of a character, as shown in step 208. If the DTMF tone is an EOC marker, in step 210 the control unit 64 will retrieve the string of numeric values that were received and stored as a result of step 206 and map them to the corresponding alpha¬ numeric character. The precise mapping procedure is simply the reverse of the encoding ' scheme described above and exemplified in Fig. 6B. As is illustrated in Fig. 6B, a DTMF tone burst "6" followed by an EOC marker translates into the letter "M". The alpha¬ numeric character "M" is stored in memory in step 210, and the control unit 64 returns to step 202 to await information regarding the next DTMF tone from the DTMF receiver 66. The procedure is repeated until the message "Meet me at 8" is stored in memory by the control unit.

If in step 208, the detected DTMF tone is determined not to be an EOC marker code, the control unit 64 determines in step 212 whether the DTMF tone is an EOD marker code. For example, in the sequence 198 shown in Fig. 6B, the tone burst "#" represents an EOD marker code which is detected by the control unit 64. Assuming a valid EOD marker code is received, the control unit in step 214 causes the entire decoded sequence of alpha-numeric information from step 206, which had followed the most recent SOD marker code, to be stored in memory for subsequent retrieval by the cellular telephone user. The control unit 64 then causes the memory location pointer in the control unit to advance to a new storage location in the RAM 106. Therefore, the cellular telephone 50 is set to store the next alpha-numeric information sequence received by the cellular telephone 50, and the control unit 64 returns to step 200.

The handset 52 preferably includes a flashing light or some other means driven by the control unit 64 for indicating that a message, whether alpha-numeric or numeric, has been received. Thus, the cellular telephone user will be notified that a message has been received and can proceed to retrieve the message using the function keys on the keypad 62. For example, the user can scroll through the stored messages using the display 60, for example, using conventional memory access techniques. As a result, the cellular telephone 50 stores and retrieves multiple alpha-numeric information sequences just as it stores and retrieves multiple numeric sequences as is described above. Moreover, the cellular telephone user is able to retrieve telephone numbers from memory and automatically dial the number using the cellular telephone 50. The handset key pad 62 includes function keys FCN. which permit easy retrieval of the information stored in memory using conventional microprocessor techniques within the control unit 64.

While the cellular telephone 50 is described primarily in the context of providing for the receipt and storage of information during a telephone conversation, the information may be processed similarly while the telephone is unattended. The system program for the control unit 64 is designed to "pick up" and answer an incoming call when such a call arrives. Thereafter, the information is received and stored in the same manner as when a conversation is occurring.

More specifically, the system program provides that the cellular telephone will respond automatically to an incoming call without requiring user intervention. By pressing a predefined sequence of keys (or a dedicated key) on the keypad 62, the system program is set to an answer mode such that when an incoming call is detected, the cellular telephone 50 will not wait for the user's request to answer the call (which conventionally is done by depressing the SEND key, for example). Instead, the cellular telephone 50 automatically answers the call as the control unit 64 implements its system program which establishes the two-way radio communication link between the caller and the cellular telephone 50.

After the two-way communication line has been established, the cellular telephone 50 generates a tone or plays back a prerecorded message signaling the caller to enter an alpha-numeric message via the keypad on the caller's telephone. At such time, the caller may enter an alpha-numeric message in the same manner as is described above with respect to the various examples. The voice recorder 75 is used when playing back a prerecorded message, the message being input into the audio and data processor 72 by way of line 250. The message on line 250 is processed in the same manner as would be a voice signal on line 251 from the microphone 58, and the system program for the control unit 64 causes the message to be communicated to the caller by way of the rf circuit 68. As is shown in Fig. 3, the solid state voice recorder 75 may include a solid state recorder 255, such as the MSM6388 which is commercially available from Old Data. A non-volatile memory 260 is used to store the digitized message for subsequent play back. In order to record the message for play back, the user dictates the message into the microphone 58, and the message is digitized and stored in the recorder 75 by way of the recorder input 265.

Fig. 7 illustrates the system logic for pre-recording a message which is then played for the caller when an incoming call is received and the cellular telephone 50 is in the "pick up" mode. The user requests to record a message by pressing a predefined key sequence (or a dedicated special function key) on the cellular telephone keypad as represented by line 284. In step 285, the control unit 64 checks to see whether a request to record a message has been received. Upon receiving this request, in step 287 the software program running on the cellular telephone control unit 64 will enable recording by enabling the solid-state recorder 255 via control line 267. Although a separate solid-state recorder 255 is used to record the message, it will be appreciated that other recording means (analog or digital) may similarly be used in accordance with the invention. In step 289, the software program generates a tone to signal the user to start speaking into the microphone 58. This signal can be an audible signal via the earpiece 56, a visible signal via the display 60, an audible and visible signal, etc.

During recording in step 291, the software program monitors the memory usage in memory 260. If a memory overflow condition occurs as in step 293, the control unit 64 terminates recording in step 295 by disabling the solid-state recorder 255 through control line 267. The control unit 64 also notifies the user of the error condition by generating an error signal such as an audible and visual signal.

If the user presses a key during recording, the software program is interrupted. In the preferred embodiment, the software program responds to keys as follows: 1. If the terminate recording key is pressed (this can be, for example, the END key used to terminate the telephone connection, or it can be any predefined key sequence), as in step 297, the software program in step 299 terminates recording (turn off solid-state recorder) and updates internal data structures to reflect that a valid message exists in memory. The control unit 64 then returns to the original state in step 285.

2. If the abort recording key is pressed (this can be the CLR key or any other predefined key combination), as in step 301, the software program terminates recording (turn off solid-state recorder 255) and, in step 303, updates internal data structures to reflect that a valid emergency message does not exist in memory. The control unit 64 then returns to step

285.

3. If any other key or key sequence is pressed, the input is ignored, as represented in step 305, and the software program continues recording. The recorder 75 also may serve as an electronic voice mailbox which allows the caller to leave a message in the event the cellular telephone 50 is unattended. The cellular telephone 50 "picks up" the incoming call automatically, as is described above. The control unit 64 enables the solid-state recorder 255 by way of control line 267 such that the prerecorded message begins to play. The recorder 255 retrieves the prerecorded message from the memory 260 through address/data bus 310. The prerecorded message invites the caller to record his or her own message to the user, and the control unit via control line 267 switches the recorder 255 to the record mode. As a result, the audio signal on the audio receive line 76 is input directly into the recorder 255 by way of input 315. The caller's message is digitized by the solid state recorder 255 and is stored in the memory 260 for subsequent retrieval by the user. To retrieve and play back the message, the user presses the appropriate function key(s) which cause the control unit 64 to instruct the solid- state recorder 255 to retrieve the recorded message from memory 260. The recorder 255 converts the digitized recording to an analog signal which is provided to the audio processor 100 by way of line 250. The message is then played through the earpiece 56.

Referring briefly back to Fig. 2, an alternate embodiment of the cellular telephone 50 includes a modem/facsimile machine interface 350 which is used to interconnect a modem or facsimile machine 352 (sometimes referred to below as "modem/facsimile") to the transceiver 54. Fig. 8 illustrates an exemplary interface 350 which enables the cellular telephone 50 to make and receive telephone calls from a modem or facsimile machine. The interface 350 includes a dedicated I/O jack 353 to which the input and output of the modem or facsimile machine is connected. Line 355 serves as a bi-directional data line between the cellular telephone and the modem/facsimile machine. Coupled to the data line 355 is a ring generator 356 which is enabled by the TIP control line 358 from the control unit 64. Line 360 is used to provide to the ring generator 354 the RING signal from the control unit 64. The output of the ring generator is coupled, via line 361, to the data line 355. Resistor R serves as a pull-up resistor on the data line 355, and coupling capacitor C connects the data line to the bi-directional operational amplifier 362. A signal on line 363 is amplified by the amplifier 362, and the amplified signal is provided on the data line 355. The signal on data line 355 is amplified by the amplifier 362, and the amplified signal is provided on line 364. A control line 365 (Fig. 2) leading to the control unit 64 is connected to the data line 355 and is used to detect whether the modem 352 is on or off hook. The interface 350 includes three switches SI, S2, and S3 which are set in accordance with whether the telephone 50 is being used in a normal mode or a data mode. When communicating directly between modems or facsimiles at both the calling and receiving ends, switch S2 is used to couple the buffered output of the audio processor 98 on line 363 through the amplifier 362 to the data line 355. Simultaneously, switch S3 disconnects the microphone 58 from the input of the audio processor 100 and connects the input to the audio processor 100 to line 364. Also simultaneously, switch SI is used to disconnect the input of the DTMF receiver 66 from the audio path 76 and, in addition, connects the DTMF receiver 66 input to line 364 as illustrated. Thus, when the cellular telephone is in the data mode, the switches S1-S3 are in the positions shown in phantom in Fig. 8. Otherwise, the switches S1-S3 are in their normal positions as shown, and the cellular telephone 50 operates normally in the manner described above.

Describing now the procedure for placing a call through the modem/facsimile 352, reference is made to Fig. 9. The control unit 64 is programmed so that the user can set the cellular telephone 50 in the "Modem/Fax Connection" mode by pressing a sequence of keys (or a dedicated special function key) as represented by line 399 on the cellular telephone keypad 62. The system program checks in step 40 whether the user has entered such a request. Upon receiving the request, the software program through the control unit 64 sets switches SI, S2 and S3 to the data mode as represented in step 402. In step 404, the control unit 64 is monitoring the hook state of the modem/facsimile 352 by way of line 365. When the control unit 64 detects an OFF HOOK state, it awaits the receipt of DTMF tones from the modem/facsimile 352. Modems typically dial all digits of a telephone number back to back (there are no long periods between individual digits). In step 406, the software program detects each dialed digit on line 364 using the DTMF decoder and, in step 408, stores such digit into a temporary memory location. After the last digit in the back-to-back sequence is detected, the system program waits the time out period in step 410. After the time out in step 410, the system program in step 412 determines whether any additional DTMF tones were received. If not, the control unit 64 accepts the digits received until that point as the complete number to dial. If an additional DTMF tone is received during such timeout, the digit is stored and step 410 is repeated. In step 414, the control unit 64 uses the complete number to place a call throug cellular means (this is the same as if the user entered a telephone number manually an initiated a call). After the connection is made, as determined by the control unit 64 in ste

416, the modem/facsimile on both sides of the connection identify themselves and set u transmission rates, etc., as is conventional. The connection is then maintained in step 418.

If the connection is lost for some reason, or an ON HOOK state is detected from the modem/facsimile 352, the cellular connection is automatically terminated as represented in step 420. The steps taken by the control unit 64 in terminating the connection are equivalent to the steps taken when the user presses the END key on a conventional cellular telephone to terminate a cellular connection he/she initiated. At any time, the user may press a predefined function key(s) as represented by line 421 to cause the telephone 50 to return to the normal mode by appropriately setting switches S1-S3 as in step 422.

With respect to receiving a call through a modem or facsimile 36 (Fig. 1), reference is made to Fig. 10. Again, the user can set the cellular telephone 50 in "Modem/Fax Connection" data mode by pressing a sequence of keys (or a dedicated key) on the cellular telephone keypad 62 as represented by line 449 and which is detected in step 450. Upon receiving the request, the software program in step 452 adjusts the switches SI, S2 and S3 to data mode, as is shown in Fig. 8. In this mode, the control unit 64 is monitoring the hooked state of the modem/facsimile 352. When the cellular telephone 50 receives a call as detected in step 454, it activates the ring generator 356 (Fig. 8) by way of line 360 (Figs. 2 and 8). This causes ring pulses to be generated in step 456 on line 361 that are similar to the ring pulses generated by the Central Offices for Land lines. Modem/facsimiles generally have means of detecting these pulses. The modem/facsimile 352, after detecting the ring pulses, will answer the call by going to an OFF HOOK state. In step 458, the control unit 64 detects the change on line 365 (Figs. 2 and 8) and answers the call by causing the transceiver 54 to answer the incoming call in step 460 by automatically picking up on the call. Once the connection is made and maintained in step 462, the modem/facsimiles on both sides of the connection identify themselves and set up transmission rates, etc. using standard protocol. If the connection is lost, or an ON HOOK state is detected from the modem/facsimile, the cellular connection is automatically terminated as represented in step 465. The steps taken to terminate the connection are similar and equivalent to the steps taken when the user presses the END key to terminat a cellular connection he/she initiated. Again, in step 467, the user may switch to th normal mode by pressing the appropriate predefined key(s).

Briefly referring to Fig. 11, a detailed schematic diagram of a substantial portio of the cellular telephone 50 of Fig. 3 is shown. The specific interconnections between th integrated circuits used for the control unit 64, DTMF receiver 66, audio and dat processor 72, etc. are illustrated. The rf circuit 68 and solid-state recorder 75 are no shown although the manner in which they are interconnected will be apparent to thos having ordinary skill in the art. The integrated circuits used in the circuit of Fig. 1 include the preferred circuits described above, although several other alternatives ar equally applicable.

Although the invention has been shown and described with respect to certai preferred embodiments, it is obvious that equivalents and modifications will occur to other skilled in the art upon the reading and understanding of the specification. The presen invention includes all such equivalents and modifications, and is limited only by the scop of the following claims.

Claims

CLAIMS 1. A mobile telephone system, said system comprising: means for transmitting a modulated radio frequency carrier signal with alpha¬ numeric information encoded thereon; and a mobile telephone for receiving and storing said alpha-numeric information, said telephone comprising: means for receiving said carrier signal; decoding means for detecting and decoding said alpha-numeric information on said carrier signal; means for storing said alpha-numeric information in memory in said telephone; and means for retrieving said stored information.

2. The system of claim 1, wherein said encoded alpha-numeric information on said carrier signal comprises a sequence of at least one dual-tone multifrequency tone, and said decoding means for detecting and decoding comprises a dual-tone multifrequency tone decoder.

3. The system of claim 2, wherein said decoding means operates during a telephone voice conversation on said telephone.

4. The system of claim 2, wherein said means for receiving comprises demodulating means for obtaining an electrical audio signal representing said sequence of at least one dual-tone multifrequency tone, and wherein said audio signal serves as the input to said tone decoder.

5. The system of claim 4, wherein said audio signal also serves as the input to an audio processor which processes voice information on said audio signal.

6. The system of claim 2, further comprising a call station at an opposite end of said telephone system for generating said dual-tone multifrequency tones representing said alpha-numeric information which are provided to said transmitting means for encoding said information on said carrier signal.

7. The system of claim 6, wherein said call station comprises a telephone having a dual-tone multifrequency generator for generating said dual-tone multifrequency tones.

8. The system of claim 6, wherein said call station comprises computer means for generating said dual-tone multifrequency tones.

9. The system of claim 1, wherein said means for storing comprises means for storing multiple segments of said alpha-numeric information which are transmitted separately.

10. The system of claim 9, wherein said means for retrieving comprises a display and means for displaying said alpha-numeric information on said display.

11. The system of claim 1, wherein said alpha-numeric information comprises a telephone number and said mobile telephone further comprises means for initiating automatic dialing means for dialing said telephone number through said telephone after said telephone number has been received and stored.

12. A mobile telephone for receiving and storing alpha-numeric information, said telephone comprising: means for receiving a modulated radio frequency carrier signal having alpha-numeric information encoded thereon; means for detecting and decoding said alpha-numeric information on said carrier signal; means for storing said alpha-numeric information in memory in said telephone; and means for retrieving said stored information.

13. The telephone of claim 12, wherein said means for detecting and decoding comprises a dual-tone multifrequency tone decoder.

14. The telephone of claim 12, further comprising means for interfacing said telephone with at least one of a modem and facsimile.

15. The telephone of claim 12, further comprising recorder means for at least one of recording a message received on said carrier signal and playing a prerecorded message so as to be received by a party calling said telephone.

16. The telephone of claim 15, wherein said recorder means comprises a solid- state recorder.

17. The telephone of claim 16, wherein said solid-state recorder digitizes and stores said message in a memory when recording said message.

18. The telephone of claim 15, further comprising means for automatically picking up upon receipt of an incoming call and means for enabling said recorder means so that said message received on said carrier signal is recorded.

19. The telephone of claim 12, wherein said alpha-numeric information comprises a telephone number and said mobile telephone further comprises means for initiating automatic dialing means for dialing said telephone number after said telephone number has been received and stored.

20. The telephone of claim 12, wherein said means for detecting and decoding said alpha-numeric information is operative during a telephone voice conversation on said telephone.

21. The telephone of claim 12, wherein said encoded alpha-numeric information on said carrier signal comprises a sequence of at least one dual-tone multifrequency tone, said means for detecting and decoding comprises a dual-tone multifrequency tone decoder, said means for receiving comprises demodulating means for obtaining an electrical audio signal representing said sequence, and wherein said audio signal serves as the input to said tone decoder.

22. The telephone of claim 21 , wherein said audio signal also serves as the input to an audio processor which processes voice information on said audio signal.

23. The telephone of claim 12, wherein said means for storing comprises means for storing multiple segments of said alpha-numeric information which are transmitted separately.

24. The telephone of claim 23, wherein said means for retrieving comprises a display and means for displaying said alpha-numeric information on said display.

25. The telephone of claim 12, wherein said alpha-numeric information comprises a telephone number and said mobile telephone further comprises means for initiating automatic dialing means for dialing said telephone number through said telephone after said telephone number has been received and stored.

26. A method for receiving and storing alpha-numeric information using a mobile telephone comprising: monitoring the demodulated audio signal produced by a receiver in said telephone; detecting one or more tones in said audio signal; decoding said one or more tones to produce a data segment representative of an alpha-numeric character; and storing said alpha-numeric character for subsequent retrieval.

27. The method of claim 26, wherein each of said tones comprises a dual-tone multifrequency (DTMF) tone.

28. The method of claim 26, further comprising the step of repeating said detecting, decoding and storing steps, whereby plural alpha-numeric characters are stored to form an alpha-numeric message.

29. The method of claim 28, further comprising the step of detecting a dedicated tone or series of tones in said audio signal representing the start of the alpha-numeric message and detecting a different dedicated tone or series of tones in said audio signal representing the end of the alpha-numeric message.

30. The method of claim 28, wherein said one or more tones representing each of said alpha-numeric characters are separated from the tones of a subsequent alpha-numeric character by an end-of-character tone or series of tones.