Abstract:
A telephone control unit  12  allows the calling party to optionally select either a standard telephone call or a voice-mail transmission. If a voice-mail message is selected, the system allows the user to dictate the message which is then analog-to-digital converted and stored in memory. Once the user selects the receiving party&#39;s telephone number, the system dials the number and sends a header signal to the receiving unit indicating that a voice-mail transmission is desired. If the receiving unit detects the voice-mail header, it sends an acknowledgment signal, whereby the transmitting unit digitally compresses the stored voice-mail message and transmits the compressed message through the telephone network to the receiving site. The receiving site then flashes an indicator to the user that voice-mail is waiting. Upon a user replaying a voice-mail signal, the receiving site decompresses and digital to analog converts the signal for reproduction by the user.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to the telephone art and, in particular, to a combination telephone and voice-mail transceiver. 
     Answering machines are commonly available devices which allow the receiving party of a telephone call to elect to store an incoming caller&#39;s message to an electronic storage medium. Thus, if the receiving party is not available to take the call, or if he or she is available yet elects not to directly talk with a calling party, they may simply allow the answering machine to store the caller&#39;s voice message. 
     In addition, voice-mail systems have been created which allow a calling party the opportunity to record for later playback by the receiving party a given communication. Voice-mail systems, however, are normally either telephone company provided or are provided by companies on private branch exchanges. Thus, they are not generally available to the public, to the same level that answering machines have become commonplace. In addition, with telephone company provided voice-mail, as with a standard answering machine message, the calling party spends total message real time on the telephone line while the message for the receiving party is being recorded, thereby incurring a billing for the entire real time use of the telephone network. 
     As more people become familiar with voice-mail, there is a growing tendency to utilize its services, but for the fact that it is only available on PBX and via telephone company provided service as described above. It would be desirable, therefore, if a calling party calling from a standard office or residential telephone unit would be given the opportunity to select making a standard call in real time or recording and transmitting a voice-mail message to his or her receiving party. 
     In addition, it would be desirable if the calling terminals provided voice-mail reception capabilities with a convenient notice and access by the telephone terminal users. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention, therefore, to provide a telephone control unit which provides, in addition to standard telephone transmit and receive capabilities, the ability to transmit and receive voice-mail messages over the telephone network. 
     It is a further object of the present invention to provide the above telephone control unit wherein messages which are transmitted are first compressed to thereby reduce the real time telephone network phone usage and thereby reduce cost of operation for the telephone control unit user. 
     These and other objects of the invention will become apparent upon review of the specification and claims which follow. 
     In summary, a telephone control unit is adapted for both transmitting and receiving voice-mail messages. It comprises a voice-mail transmitter which includes a detector that detects that a voice-mail message is to be sent. The transmitter further includes storage capability to store the voice-mail messages in memory. A compression means compresses the stored voice-mail message. 
     A predetermined header is then attached to the compressed voice-mail message. The header and compressed voice-mail message are then transmitted over the telephone network to a user-dialed voice-mail receiver. The voice-mail receiver includes a receiver for receiving the message over the telephone network. A detector then detects the presence of a predetermined voice-mail header in the message and, in response to header detection: 1) strips off the voice-mail header; 2) decompresses the voice-mail message and 3) transduces the voice-mail message upon user-desired replay. 
     In the preferred implementation of the invention, the transmitter further includes an analog-to-digital converter for converting the voice-mail message to a digital format. The digital signal is then stored and processed through a digital compression algorithm before being transmitted over the telephone network with the attached header signal. The receiver further includes a digital-to-analog converter which converts the received digital messages from the transmitter over the telephone network into an analog signal format. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 if a perspective view of the preferred embodiment of the inventive telephone control unit and illustrates the use of a voice-mail mode switch, indicator light, and a voice-mail waiting indicator light; 
     FIG. 2 is a block diagram illustrating the principal components, and their interrelationship, of the preferred embodiment of the voice-mail transceiver; 
     FIGS. 3A and 3B are a logic flow diagram illustrating the preferred embodiment of the logical sequence performed by the inventive voice-mail transmitter; and 
     FIG. 4 is a logic flow diagram illustrating the preferred logic step sequence performed by the inventive voice-mail receiver. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates a perspective view of the preferred embodiment of the telephone control unit indicated generally at  10 , which allows for the transmission and reception of voice-mail. Shown is a base unit  12  which contains the principal electronics for the voice-mail transceiver  10 . On the operating base plate of the base unit  12  is formed a conventional telephone keypad arrangement  14  which may include standard speed dialing pads. Formed in the upper surface of base unit  12  is a cradle recess  16  which is adapted to receive a conventional handset  18 . Provided within the cradle recess  16  is a standard hook switch  20 . The handset  18  includes a conventional microphone  22  in its mouthpiece and a conventional speaker  24  at its earpiece. The handset  18  connects to the base unit  12  through a conventional coiled cord  26 . 
     As is described more thoroughly herein below, the present telephone control unit  10  allows a user to both transmit and receive voice-mail messages. Thus, provided on the faceplate of base unit  12  is a switch  30  which the user activates when desirous of placing a voice-mail transmission. To reflect that the telephone control unit  10  is in the voice-mail mode, a provided indicator  32  (which, preferably, is a conventional light-emitting diode), lights to indicate voice-mail mode. 
     In addition, also provided in the faceplate of base unit  12  is an indicator  34  (also, preferably, a light emitting diode) which lights to indicate to a user that he or she has voice-mail waiting to be heard. Should the user desire to replay his or her voice-mail, a provided switch  36  (also in the faceplate of base unit  12 ) is activated by the user to thereby allow message replay. 
     The telephone control unit  10  in the conventional manner connects via standard cord  40  and module plug  42  to the telephone network. 
     FIG. 2 is a block diagram which illustrates the preferred construction of the voice-mail transceiver shown in FIG.  1 . As with FIG. 1, shown is a handset  18  which includes a microphone  22  in the handset and a speaker  24  in the ear portion of the handset. The handset connects to the base unit, indicated generally at  12 , by means of a cable  26 . 
     Provided on the base unit  12  are a voice-mail mode switch  30 , a voice-mail on indicator  32 , a voice-mail waiting indicator  34  and a voice-mail replay switch  36 . 
     Also provided on base unit  12  is a standard keypad  14  which may also include speed dialing pads. 
     The connection from the base unit  12  to the telephone network is via a cable  40  and a standard modular plug  42 . 
     At the heart of the voice-mail transceiver control unit is a central processing unit (CPU)  50 . In the conventional manner, central processing unit  50  includes read-only memory (ROM)  52 . A program which resides permanently on the ROM  52  provides the instruction set for the CPU allowing it to power-up and perform many of the functions described below. 
     The CPU  50  has associated random access memory (RAM)  54  which CPU  50  uses for the purpose of both reading and writing digital signals to perform the functionality described below. Also associated with CPU  50  is a date/time module  53  used by CPU  50  to date and time tag messages as described below. CPU  50  is connected to the handset  18  and to the cord  40  and connector module  42  through an analog-to-digital (A/D)/digital-to-analog (D/A) converter module  60  and a switching system  70 . 
     Further, the CPU  50  connects through an interface circuit  62  to the voice-mail on indicator  32 , voice-mail mode switch  30 , voice-mail waiting indicator  34 , voice-mail replay switch  36  and the keypad  14 . 
     FIG. 3 is a logic flow diagram which details the logical steps performed by the CPU  50  in the course of its function as a voice-mail transmitter. From the begin mode  100  which may reflect the user pulling the handset  18  out of the cradle, and thereby activating hookswitch  20  “off-hook”, the system first enters a decision block  102  to determine if the voice-mail mode has been selected. The voice-mail mode is selected by a user activating the voice-mail mode switch  30  as shown in FIGS. 1 and 2. If the voice-mail mode has not been selected, the logic allows a user to place a real time call as normal, as shown in block  104 . If, however, the voice-mail mode has been activated, the system enters block  106  and transmits a message to the caller, namely “dictate message then press # key”. 
     The user&#39;s message is then analog-to-digitally converted and stored in memory with an associated date/time tag at block  108 . At decision block  110 , it is determined whether or not the # key has been pressed. If it has not, the system reverts to the A/D—D/A conversion block  108 . If, however, the # key  110  has been pressed, the system reproduces to the caller the message, “enter the number of the party you want to receive your voice-mail” at block  112 . The user may then manually enter the receiving party&#39;s number via the keypad or, if the keypad is provided with an appropriate speed dial number, the user may simply activate the appropriate keypad, whereby the system then loads the receiving party&#39;s phone number at block  114 . 
     To reduce the time that the telephone network is being accessed in order to transmit the voice-mail message, the user&#39;s stored digital message is then compressed by conventional digital data compression means at block  116 . 
     The system then goes “off hook” and transmits over the telephone network the receiving party&#39;s telephone number, at block  120 . The system then enters a decision block  122  to determine whether or not the receiving party&#39;s unit connects to the transmitted call. If it does not connect, the system then disconnects from the telephone network (goes off-hook at block  124 ) waits a period of time at block  126 , and reinstitutes the off-hook and transmission of the receiving party&#39;s number block  120 . 
     If, however, out of decision block  122  it is determined that the receiving party&#39;s unit has answered, block  130  is entered and the transmitting unit transmits a predetermined header signal to the receiving party&#39;s unit to thereby indicate that a voice-mail message is to be transmitted. The system then, at decision block  132 , determines whether or not it has received a voice-mail acknowledgment signal from the receiving unit within a five second period. If the voice-mail acknowledgment signal is not received within the five second period, the system proceeds to block  124  to thereby disconnect and repeat the process. 
     If, however, at block  132  a receiving party acknowledgment signal is received, the system proceeds at block  140  to transmit the compressed voice-mail message. When a complete stored and compressed voice-mail message has been fully transmitted, the transmitter enters block  142  and transmits a predetermined end-of-message command signal. This results in a hang-up, at block  144  of the transmitting unit. 
     Operation of the receiving portion of the voice-mail transceiver is illustrated with respect to the logic flow diagram set forth in FIG.  4 . 
     Here, the receive mode begins at  200 . First, the system operates to detect whether or not an incoming call has been detected in which event the receiving telephone unit goes “off-hook” at block  202 . A decision block  204  is then entered to determine whether or not the received message contains the predetermined voice-mail header signal from the transmitting unit. If the received signal does not include the transmitted header signal, block  210  is entered and the system activates the ringer of the associated telephone unit and processes the incoming message as a standard real time telephone call. 
     If, however, at block  204  the predetermined voice-mail header is received, the system responds at block  212  to strip off the header. 
     After the header is stripped off of block  212 , block  214  is entered and the receiving unit transmits a predetermined voice-mail acknowledgment signal back to the transmitting unit thereby letting the transmitting unit know that a voice-mail message may be transmitted. 
     At block  216 , the receiving unit receives and stores the compressed voice-mail message from the calling unit. At decision block  218 , the receiver determines whether or not an end-of-voice-mail signal has been received. If it has not, the system iterates to block  216 . However, if an end-of-voice-mail signal is transmitted by the calling unit, the receiver responds at block  220  by hanging up (going on-hook) and providing an indication to the user at the receiver that a voice-mail message is waiting to be reviewed. 
     Operation of the voice-mail transceiver for purposes of allowing a user to review his or her voice-mail messages begins at  300 . The system first determines at decision block  302  whether a user has commanded that the stored voice-mail messages be replayed. If no such command is received, the system iterates back to the input of block  302 . However, upon a user indicating (as by the voice-mail replay button  36 ) that he or she wishes to replay any stored voice-mail messages, the system then enters block  304  and decompresses the stored voice-mail message. The decompressed voice-mail message is passed to block  306  where it is digital-to-analog converted back into the original voice-mail message as first recorded at the transmitter. The system then enters block  308  at which point the system reproduces the voice-mail message to the user. 
     In summary, a telephone control unit which includes a voice-mail transceiver has been described in detail. The transceiver allows the calling party to determine whether or not voice-mail or standard calls are desired. And, if a voice-mail transmission is desired, the caller&#39;s message is compressed to thereby reduce telephone network usage. 
     While a preferred embodiment of the invention has been described in detail, it should be apparent that many modifications and variations thereto are possible, all of which fall within the true spirit and scope of lo the invention.