Abstract:
In an electronic mail system utilizing a computer network, the received mail is accumulated in a mailbox corresponding to the destination address mail ID for the purpose of management. Therefore, if the received mail exceeds the specified capacity of the mailbox, any additional mail is not accumulated and dispersed. The received mail is of varying type, having different application purposes. Mail having a specified application purpose may or may not be required to be accumulated, but if the mail is never received, the contents of the mail cannot be confirmed and it has been impossible to judge the necessity of accumulation of such mail. Electronic mail is identified as to its application purpose, and a mailbox is provided for accumulating mail for each mail ID preset for each user of the electronic mail system, and for each application class of mail content. A mail server stores and reads mail to and from the mailbox through designation of the mail ID and mail application class.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to control of a mailbox as a mail accumulating unit in an electronic mail system for exchanging information such as characters and voice in the form of electronic mail between terminals such as personal computers through a computer network.  
           [0002]    In a conventional electronic mail system as shown in FIG. 16, upon issuance of a mail transmission request from a user, a mail server  30  accumulates mail in a mailbox  32  prepared for each user ID indicated in the destination address of the mail. A user can read the mail sent thereto from the mailbox  32  corresponding to the user ID. When a plurality of items of mail are accumulated in the mailbox  32 , these are indicated in the form of a list, and the contents of the selected items of mail are read out. Since the mail server  30  is formed of an external memory, if the amount of mail exceeds the specified capacity of the mailbox  32 , a portion of this mail is no longer accumulated and dispersed.  
           [0003]    Electronic mail systems are used for a variety of application purposes and for private and business messages. Moreover, the same electronic mail can be transmitted to a plurality of destination addresses, due to the general address function in which the same mail can be stored in a plurality of mailboxes. As a result, an online shopping system provider can transmit electronic mail for product publicity (e.g., electronic mail advertisements) to a plurality of users.  
           [0004]    In such conventional electronic mail systems, since a user receives electronic mail transmitted for various application purposes, it often happens that a large amount of electronic mail publicity or advertisements exceed the specified capacity of the user&#39;s mailbox, so that important mail other than publicity mail or advertisements cannot be received. Therefore, there is a need to avoid this non-receiving condition for electronic mail.  
           [0005]    Moreover, a list of the received mail indicates only the titles of the mail received, resulting in a problem in that the application purpose and importance of the mail (e.g., business or advertising) cannot be understood until the mail is received and its contents checked.  
         SUMMARY OF THE INVENTION  
         [0006]    It is an object of the present invention to overcome the above-described problems of prior art electronic mail systems.  
           [0007]    [0007]FIG. 1 is a schematic diagram of a system in accordance with the present invention which solves the problems of prior art systems explained above.  
           [0008]    In order to solve the above problems, the present invention provides an electronic mail system for exchanging electronic mail between terminals via a network  16 , comprising mailboxes  20 ,  23 ,  24  for storing messages for each mail ID  21  and corresponding class  22  of mail content preset for each user of the electronic mail system. User terminals  10 ,  13  are mail terminals which have mail transmitting units  11 ,  14  for requesting transmission of items of mail by designating, at the time of electronic mail transmission, the mail ID  21  indicating the transmission destination address, the class  22  of mail content and the message content. A mail server  17  has a mail storing unit  18  to store items of mail in the mailboxes  20 ,  23 ,  24  corresponding to the mail ID and class of mail designated by the user terminal which transmits the mail. Moreover, the electronic mail system of the present invention also comprises user terminals having mail receiving units  12 ,  15  to request, at the time of receiving electronic mail, forwarding of mail to the mail server  17  by designating the mail ID  21  and class  22  of mail contents. The mail received from the server  17  is read out by a mail reading unit  19  which reads, upon reception of an instruction for the mail ID  21  and class  22  of the mail content, the mail from one of the mailboxes  20 ,  23 ,  24  corresponding to the designated mail ID  21  and class  22  of mail.  
           [0009]    These together with other objects and advantages which will be subsequently apparent, reside in the details of the construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a block diagram of an electronic mail system in accordance with the present invention;  
         [0011]    [0011]FIG. 2 is a block diagram of the system of the present invention as implemented using a general purpose computer;  
         [0012]    [0012]FIG. 3 is a diagram of a transmission mail format in accordance with the present invention;  
         [0013]    [0013]FIG. 4 is a diagram illustrating the format of a mailbox management table in accordance with the present invention;  
         [0014]    [0014]FIG. 5 is a diagram illustrating the format of a mail management table in accordance with the present invention;  
         [0015]    [0015]FIG. 6 is a diagram illustrating the format of a message text table in accordance with the present invention;  
         [0016]    [0016]FIG. 7 is a flow chart illustrating the processing which occurs in a mail transmitting unit in a user terminal in accordance with the present invention;  
         [0017]    [0017]FIG. 8 is a diagram illustrating an example of a display screen designating transmission of electronic mail in accordance with the present invention;  
         [0018]    [0018]FIG. 9 is a flow chart illustrating the processing performed by a mail storing unit of a mail server in accordance with the present invention;  
         [0019]    [0019]FIG. 10 is a flow chart illustrating the processing of a mail receiving unit of a user terminal in accordance with the present invention;  
         [0020]    [0020]FIG. 11 is a diagram illustrating a display screen listing received electronic mail in accordance with the present invention;  
         [0021]    [0021]FIG. 12 is a diagram illustrating a display screen for received electronic mail in accordance with the present invention;  
         [0022]    [0022]FIG. 13 is a flow chart for illustrating the processing performed by a mail reading unit of a mail server in accordance If with the present claimed invention;  
         [0023]    [0023]FIG. 14 is a block diagram of the system of the present invention as implemented utilizing the internet;  
         [0024]    [0024]FIG. 15 is a block diagram of the system of the present invention as implement utilizing a cable television network; and  
         [0025]    [0025]FIG. 16 is a block diagram of a prior art electronic mail system. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    A preferred embodiment of the present invention will be explained below with reference to the accompanying drawings.  
         [0027]    [0027]FIG. 1 is a block diagram of the system of the present invention, composed of user terminals  10 ,  13  which are mail terminals for instructing transmission and reception of electronic mail, and a mail server  17  for processing electronic mail on the basis of the instructions issued from the user terminals  10  and  13 .  
         [0028]    The mail server  17  transmits and receives electronic mail based on instructions from the user terminals  10  and  13 . The server  17  has a mailbox  20  for accumulating a plurality of items of electronic mail. The mailbox  20  is provided on a storage device of the mail server  17  to store the mail requested to be transmitted and to identify the user ID. For example, a subdirectory is set for each user ID under the control of the mail storage directory in order to store a data file for each class of mail received under the control of the subdirectory. The mailbox  20  accumulates and holds the mail for each mail ID  21  as the electronic mail destination address and class  22  of mail. Since the mailbox  20  is classified for each category or class of mail, the number of items of mail which can be accumulated in the mailbox can also be changed depending on the application purpose. Therefore, a user is capable of making reference to only the most recent mail having higher priority by setting the number of items of mail to be accumulated in the mailbox, which have a lower priority to a value lower than that of another mailbox, depending on the class of mail application.  
         [0029]    A user who desires transmission or reception of electronic mail issues an instruction for transmission or reception of electronic mail to the mail server  17  from a terminal  10 . For the transmission of electronic mail, a user provides a mail ID to the mail transmitting units  11 ,  14  of the terminal  10 . The mail ID is an identifier indicating a destination address of the mail, a mail class indicating the application of the mail and a message. The mail transmitting unit  11  transmits the contents provided by the user to the mail server  17  through the communication network  16 . The mail server  17  stores, on the basis of the contents, the mail in the mailboxes  23 ,  24  corresponding to the mail ID  21  which is an identifier indicating the destination address and class of mail  22 .  
         [0030]    For the reception of electronic mail, the identifier indicating the destination address of an item of mail as the reception object and a class of mail indicating a mail application are provided to mail receiving units  12 ,  15  of the user terminals  10  and  13 . The mail receiving units  12  and  15  send the provided content to the mail server  17  via the communication network  16 . The mail server  17  reads the electronic mail message from the mailboxes  23 ,  24  corresponding to the mail ID  21  which is an identifier indicating destination address and the class  22  of mail on the basis of the notified content. The server  17  then sends the message read out to the mail receiving units  12 ,  15  of the terminals  10  and  13 . When a plurality of items of mail exist within one mailbox, only management data, such as the titles of the items of mail, the names of originators or the like is transmitted. The user terminals  10  and  13  display the lists on the basis of the data transmitted. Next, the mail server  17  outputs the text of the mail to be received by the terminals  10  and  13  to send the text of the mail selected from the list to the specified user terminal.  
         [0031]    [0031]FIG. 2 is a block diagram of an embodiment of the present invention as implemented utilizing a general purpose computer. An electronic mail system user notifies a mail server  30  of a personal computer communication company of transmission and reception of electronic mail via a terminal  35  coupled to the subscriber telephone network  34 . The mail server  30  is controlled by its host computer  31 , and transmission and reception of electronic mail instructed from the user terminal  35  is executed under the control of the host computer  31  through storing and reading operations to and from mailboxes  32 ,  33  . . . for each class of mail.  
         [0032]    Next, the formats of electronic mail and the mailboxes will be explained with reference to FIG. 3 to FIG. 7. As shown in FIG. 3, an electronic mail format includes a destination address ID  100  for electronic mail transmission, a transmitting user ID  101  which is an address for identifying a user as a mail originator, a mail class  102 , a title  103  and a message  104 . A mail class  102  indicates a mail application, which is set to “Business” for business communications, or to “Publicity” for the guidance of online shopping, or to “Private” for private communications.  
         [0033]    As the class setting, the data “01”, for example, may designate “Business” mail, while “02” may designate “Publicity” mail and “03” may designate “Private” mail. Classification of mail is not limited to the above classifications, and it is of course possible to classify the mail with a fewer or greater number of classifications. For example, two mailboxes for “Business” and “General” mail may be provided. In addition, it is also possible that a class may be set, for example, only to “Business” while other applications are set up as one class. Alternatively, if classes are not set up, mail may be controlled to be stored automatically in another mail box corresponding to the “Ordinary” class.  
         [0034]    The mailbox in the mail server is constituted as shown in FIG. 4 to FIG. 6. The present invention will be explained using an example where the mail contents are stored in different mailboxes for each electronic mail destination address and class of mail. FIG. 4 illustrates a mailbox management table for management of each mailbox to be used for management of an identifier indicating the destination address of electronic mail, a mailbox number corresponding to a class of mail and a position of a data file storing a message. This table is used for management of a mailbox number  107  corresponding to a mail address ID  105 , a mail class  106  and a storing directory  108  for the corresponding external memory. The mail storing directory  108  sets the subdirectory for each mail address ID  105  under the control of the mailbox directory and moreover sets the directory name in which the data file is stored for each mail class  106 . In FIG. 4, “MAILBOX” corresponds to a mailbox directory name, “AAA 1111” corresponds to a subdirectory name for each mail address ID  105  and “PUB”, “PRI” and “BUS” corresponds to data files of a message text table for storing messages for publicity, private and business mail, respectively. The message text for each mail address ID  105  and mail class  106  can be managed by storing the message text in each data file.  
         [0035]    Next, the format of each mailbox will be explained. Each mailbox is composed of a stored electronic mail management table and a message text table for storing a mail message text. FIG. 5 illustrates a format for managing electronic mail in the mailbox. For all mail in the mailbox, a mail title  109 , a flag  110  indicating whether the mail has been read out, a starting position  111  in the message text table and an ending position  112  are set for each item of mail. When a plurality of items of mail exist within the mailbox, the content of this mail management table is sent to the user terminals for display as a list.  
         [0036]    [0036]FIG. 6 illustrates a format of the message text table. Each data file located in the position designated by the mail storing directory designated in FIG. 4 (“PUB”, “PRI” and “BUS” under the control of “/MAILBOX/AAA1111”) corresponds to this table. The data representing the text of each message is stored in the message text table, at the position corresponding to the starting position  111  and the ending position  112  identified by the mail management table.  
         [0037]    Next, the electronic mail transmitting process will be explained on the basis of an example of transmitting publicity mail to “AAA1111” from the user ID “BBB2222” by referring to FIG. 7 to FIG. 9. FIG. 7 illustrates a processing flow in the mail transmitting unit  11  of the user terminal  10 . For the transmission of electronic mail, a user designates “BBB2222” as the electronic mail user ID (S 10 ) as an originator to the electronic mail transmitting unit  11  in the terminal. Then, the user designates “AAA1111” as the electronic mail address (S 11 ) for the electronic mail. The user designates “01” to indicate publicity as the class of mail corresponding to the content thereof (S 12 ), and designates “Winter Gift is Welcome” as the title (S 13 ) and also designates the message text (S 14 ). It is also possible to designate the above items by preparing an electronic mail transmitting display as shown in FIG. 8 within the electronic mail transmitting unit  11 . An example of mail as shown in FIG. 8 is prepared as publicity mail in which the transmitting address mail ID and mail title are input, publicity is designated as the class of mail, and transmission of message text is also designated. As explained with reference to FIG. 8, the class of mail is selected from among the categories of private, business and publicity, and moreover, it may also be designated directly by a user. The electronic mail transmitting unit  11  generates an electronic mail message based on the content instructed and transmits this mail to the mail server  17  (S 15 ).  
         [0038]    The flow of the message storing process in the mail server  17  which has received a transmission request, is shown in FIG. 9. Upon reception of an electronic mail message from the user terminal  10  (S 20 ), the mail server  17  obtains the sending user ID, title, mail address ID and class of mail (S 21  and S 22 ) and refers to the mailbox management table shown in FIG. 4 to identify the mailbox corresponding to the ID and class of mail. In this example, since “AAA1111” is designated as the mail address ID and “Publicity” is designated as the class of mail, the mailbox number is designated as “001”. Next, the message text is stored in the corresponding mailbox. The transmitting user ID and title are stored (S 23 ) in the mail management table of FIG. 5 and the message is stored in the message text table of FIG. 6 (S 24 , S 25 ). The message text of the mail is stored in an unused area of the message text table and the starting/ending positions and the flag which identifies that the mail is not yet read out, are set in the mail management table of FIG. 5.  
         [0039]    Next, the electronic mail receiving process will be explained by referring to FIG. 10 to FIG. 13 based on an example of receiving mail for which the user ID “AAA1111” is stored in the mailbox. FIG. 10 is a flow chart for the processing flow in the mail receiving unit  15  of the user terminal  13 . For the reception of an electronic mail message, a user instructs a class of mail based on the electronic mail ID and mail content of the user to the electronic mail receiving unit  15  in the terminal  13  (S 31 , S 32 ). It is also possible to designate reception by generating an electronic mail receiving display as shown in FIG. 11 and FIG. 12 in the electronic mail receiving unit  15 . The electronic mail receiving unit  15  sends the mail ID and class of mail to the mail server  17  (S 33 ) with the designations shown in FIG. 11 on the receiving display. When a data list of the mail documents in the corresponding mailbox is received from the mail server  17  (S 34 ), a list is displayed (S 35 ) as shown in FIG. 11, and the user is requested to select the desired mail (S 36 ). When the mail receiving unit  15  selects, for example, the mail “01”, it receives the content of the text of the message “Winter Gift is Welcome!” of mail “01” from the mail server  17  (S 37 ). The mail content transmitted is displayed in the electronic mail receiving unit  15  (S 38 ) with the display screen of FIG. 12.  
         [0040]    Next, processing in the mail server  17  will be explained with reference to the flow chart of FIG. 13. Upon reception of a request for receiving electronic mail from a user terminal  13  (S 40 ), the mail server  17  acquires the receiving ID and mail class based on the format shown in FIG. 3 (S 41 ). The server  17  refers to the mailbox management table shown in FIG. 4, identifies the mailbox corresponding to the ID and mail class (S 42 ) and sends mail list data for the selected mailbox (S 43 ). When the particular item of mail selected from the list is sent from the terminal  13 , the mail server  17  refers to the message text table to read the message corresponding to the selected mail (S 44 ) and then sends this message to the user terminal  13  (S 45 ). For the mail read out, the read flag in the mailbox management table (FIG. 5) is set to indicate that the mail has been read.  
         [0041]    An example of an electronic mail system utilizing a general purpose computer has been explained above, and this electronic mail system may be replaced with a system utilizing the internet or a CATV network as shown in FIG. 14 and FIG. 15. The only requirement is that the system accumulate electronic mail by writing into the mailbox based on each address and then read the mail based on the instruction issued.  
         [0042]    In an electronic mail system utilizing the internet  50  shown in FIG. 14, when a company user or client  52  desires, for example, to make contact with the internet  50  from a private LAN, a mail server  54  is provided within the private network. The mail server  54  is used for accumulation and management of mail for each destination address. Therefore, different mailboxes  56  may be used for various types of business, and application efficiency of the electronic mail system can be enhanced by implementing the mail server  54  with the present invention. Moreover, when a personal user desires to make contact with the internet  50  from the access point of a commercial internet provider, he can use different mailboxes for each class of mail by utilizing the present invention, because the mail server  54  is provided by the commercial internet provider.  
         [0043]    In an electronic mail system utilizing a CATV network as shown in FIG. 15, a personal computer is connected as a terminal and communication can be carried out by utilizing available space on a part of the CATV network. The personal computer  60  used as a terminal is provided with a LAN board and is connected to a CATV network through a CATV communication apparatus  62  (such as a cable modem, or the like). Within a CATV center  64 , a server  66  is provided in combination with a head end  68  for distributing the CATV programs, and the personal computer terminal  60  is provided with an application of transmission control protocol/internet protocol (TCP/IP) for LAN. As a result, the P.C. terminal  60  can operate as a client of the server  66 . Accordingly, different mailboxes may be used for each type of business content in order to realize high application efficiency for an electronic mail system by installing the mail server  66  in the CATV center  64  and implementing the present invention. Particularly, since management of both CATV users and electronic mail users can be realized at the CATV center  64 , electronic mail may be transmitted to CATV subscribers.  
         [0044]    As explained above, the present invention enables reception of electronic mail based on its application purpose, and the mail can be stored in different mailboxes based on its application, at the time of transmitting the electronic mail.  
         [0045]    Therefore, when the number of electronic mail messages to be received is determined for each mailbox, the mail to be received can be designated for each application. If electronic mail messages are frequently transmitted or received, the mail can be received based on application importance and receiving frequency through the receiving process, and based on the application purpose, so that highly efficient electronic mail processing can be realized.  
         [0046]    Since the contents of electronic mail cannot be known from only the titles displayed in the list of mail received, the application purpose for each item of mail is also stored in the mailboxes for each application purpose. As a result, electronic mail may be received selectively depending on its importance to the user, which can be understood from its application purpose.  
         [0047]    The many features and advantages of the invention are apparent from the detailed specification and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope thereof. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly all suitable modifications and equivalents may be resorted to, as falling within the scope of the invention.