Abstract:
A client is coupled to a modem pool and a server by a communication link in a wide area network. The client allows a user to browse the World Wide Web in response to user inputs entered at the client device. The communication link to the client is shared by a telephone circuit at the client end of the link. A disruption in communication with the server may occur due to a Call Waiting signal caused by an incoming telephone call, or due to another user picking up a telephone extension associated with the client. In response to such a disruption, the client saves the browsing status after which communication with the server is terminated. When the telephone line is once again available for connecting to the server, the client uses the browsing information saved to reconnect to the Web page that was displayed by the client at the time of the disruption.

Description:
RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 09/107,063, filed Jun. 30, 1998, which is incorporated herein by reference in its entirety. That application is a divisional of U.S. patent application Ser. No. 08/660,087, filed Jun. 3, 1996, now U.S. Pat. No. 5,896,444 issued Apr. 20, 1999, which is also incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. The Field of the Invention 
     The present invention pertains to the field of client-server computer networking. More particularly, the present invention relates to a method and apparatus for providing communications between a client and a server in a computer network. 
     2. The Prior State of the Art 
     The number of homes and businesses using personal computers has increased substantially in recent years. Along with this increase has come an explosion in the use of the Internet, and particularly in the use of the World-Wide Web (“the Web”). The Web is a collection of formatted hypertext pages located on numerous computers around the world that are logically connected by the Internet. Advances in network technology, particularly software for providing user interfaces to the Web (“Web browsers”), have made the Web accessible to a large segment of the population. However, despite the growth in the development and use of the Web, many people are still unable to take advantage of this important resource. 
     Access to the Web has thus far been limited mostly to people who have access to a personal computer. However, many people cannot afford the cost of even a relatively inexpensive personal computer, while others are either unable or unwilling to learn the basic computer skills that are required to access the Web. Furthermore, Web browsers in the prior art generally do not provide the degree of user-friendliness desired by some people, and many computer novices do not have the patience to learn how to use the software. Therefore, it would be desirable to provide an inexpensive means by which a person can access the Web without the use of a personal computer. In particular, it would be desirable for a person to be able to access the Web pages using an ordinary television set and a remote control, so that the person feels more as if he or she is simply changing television channels, rather than utilizing a complex computer network. 
     Computer systems often communicate data with each other over large distances using standard telephone lines (also known as “POTS,” for Plain Old Telephone Service). Often a computer does not have a telephone line dedicated solely for its own use, however. Instead, a computer often uses a telephone line that is also used for standard telephone voice communication. Such dual use of the telephone line can cause problems for computers. For example, many conventional telephone services provide a feature known as “Call Waiting,” which notifies a person involved in a telephone conversation when there is another incoming call on that line. The person receiving the new call generally is notified by an audible tone caused by a Call Waiting signal. In response, the person can either switch to the other call without disconnecting the call already in progress (a technique sometimes called “flashing”) or simply ignore the new call. However, a Call Waiting signal can severely disrupt data communications if it is received while a computer is using the line. 
     Although some communications software provides the ability to disable the Call Waiting signal, doing so has the disadvantage that the computer&#39;s user generally has no way of knowing when someone is trying to reach him by telephone. Hence, it would be desirable to avoid severe disruptions without disabling the Call Waiting capability, particularly when browsing the Web. 
     Prior art systems that have accommodated Call Waiting during modem communications have done so only in client-to-client communications, and have only handled the case of both clients and modems being programmed to handle a Call Waiting interruption. Examples of such systems are a voice-over-data modem designed by Phylon, Inc., of Fremont, Calif., and a data-only modem designed by Catapult Entertainment of Cupertino, Calif. Both products are designed for video game play over a modem, and both handle Call Waiting interruptions by detecting the interruption, signaling the other client of the condition, and then both clients terminating the phone connection to allow the incoming call to be answered. When the call is completed, one modem dials the other to resume game play. 
     These two systems do not handle a more difficult condition: that of a client modem that is designed to handle a Call Waiting interruption which is dialed into a server modem that is not. For example, such a client modem might dial into a modem pool, such as that providing Internet access, which was designed using conventional modems. Since such conventional modems were designed with the assumption that dial-up would be through a phone connection that was not to be periodically interrupted by Call Waiting, they do not support the signaling and reconnect protocols that allowed the prior art video game modems to resume a connection smoothly after a Call Waiting interruption. 
     Unfortunately, the vast majority of server modems in use in the world today are conventional modems designed with the assumption that the dial-up is through a connection not periodically interrupted by Call Waiting. Thus, as a practical matter, the prior art video game modems, which rely on the system on the other side of the phone connection as including a Call Waiting aware modem and client, do not handle a client-server modem connection that is interrupted by Call Waiting. 
     In addition to the Call Waiting feature, some telephone services provide a feature known as Caller ID. Caller ID provides a person who receives a telephone call and who has the proper equipment with the phone number from which an incoming call originates. This service can be quite useful when the person receiving the call recognizes the number. However, people sometimes receive telephone calls originating from telephone numbers with which they are not familiar. Therefore, it would be desirable to provide a Caller ID subscriber with more detailed information regarding the source of an incoming call. It would further be desirable to provide such information to a subscriber who is using the telephone line to browse the Web at the time the call is received. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     In a client system communicating with a server system over a communication link, a method is provided of responding to a disruption in communication with the server system. The communication link includes a telephone line. In response to the disruption, the client system saves the browsing status and terminates communication with the server system. The client system later reconnects to the server system and established the same browsing status as existed at the time of the disruption. 
     Other features of the present invention will be apparent from the accompanying drawings and from the detailed description which follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which: 
     FIG. 1 illustrates several client systems connected to a server system in a network. 
     FIG. 2A illustrates a client system for browsing the World-Wide Web. 
     FIG. 2B is a block diagram of an electronics unit of the client system. 
     FIG. 3 illustrates telephones, a client system, and a standard personal computer sharing one telephone line. 
     FIG. 4 illustrates the functional relationship between hardware and software in the client system. 
     FIG. 5 is a flow diagram illustrating a routine for handling an interruption in communication in the client system. 
     FIG. 6 is a flow diagram illustrating a routine for responding to a call-waiting signal. 
     FIG. 7 is a flow diagram illustrating a routine for determining a name associated with a phone number derived from Caller ID information. 
     FIG. 8 is a flow diagram illustrating a routine used by a client system for selectively notifying a user of an incoming telephone call. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A method and apparatus are described for managing communications between a client and a server in a computer network. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be evident, however, to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the present invention. 
     The present invention includes various steps, which will be described below. The steps can be embodied in machine-executable instructions, which can be used to cause a general-purpose or special-purpose processor programmed with the instructions to perform the steps. Alternatively, the steps of the present invention might be performed by specific hardware components that contain hardwired logic for performing the steps, or by any combination of programmed computer components and custom hardware components. 
     The present invention is included in a system, known as WebTV™, for providing a user with access to the Internet. A user of a WebTV™ client generally accesses a WebTV™ server via a direct-dial telephone (POTS, for “plain old telephone service”), ISDN (Integrated Services Digital Network), or other similar connection, in order to browse the Web, send and receive electronic mail (e-mail), and use various other WebTV™ network services. In the preferred embodiment, the WebTV™ network services are provided by WebTV™ servers using software residing within the WebTV™ servers in conjunction with software residing within a WebTV™ client. 
     FIG. 1 illustrates a basic configuration of the WebTV™ network according to one embodiment. A number of WebTV™ clients  1  are coupled to a modem pool  2  via direct-dial, bi-directional data connections  29 , which may be telephone (POTS, i.e., “plain old telephone service”), ISDN (Integrated Services Digital Network), or any other similar type of connection. The modem pool  2  is coupled typically through a router, such as that conventionally known in the art, to a number of remote servers  4  via a conventional network infrastructure  3 , such as the Internet. The WebTV™ system also includes a WebTV™ server  5 , which specifically supports the WebTV™ clients  1 . The WebTV™ clients  1  each have a connection to the WebTV™ server  5  either directly or through the modem pool  2  and the Internet  3 . Note that the modem pool  2  is a conventional modem pool, such as those found today throughout the world providing access to the Internet and private networks. 
     Note that in this description, in order to facilitate explanation the WebTV™ server  5  is generally discussed as if it were a single device, and functions provided by the WebTV™ services are generally discussed as being performed by such single device. However, the WebTV™ server  5  may actually comprise multiple physical and logical devices connected in a distributed architecture, and the various functions discussed below which are provided by the WebTV™ services may actually be distributed among multiple WebTV™ server devices. 
     FIG. 2A illustrates a WebTV™ client  1 . The WebTV™ client  1  includes an electronics unit  10  (hereinafter referred to as “the WebTV™ box  10 ”), an ordinary television set  12 , and a remote control  11 . In an alternative embodiment of the present invention, the WebTV™ box  10  is built into the television set  12  as an integral unit. The WebTV™ box  10  includes hardware and software for providing the user with a graphical user interface, by which the user can access the WebTV™ network services, browse the Web, send e-mail, and otherwise access the Internet. 
     The WebTV™ client  1  uses the television set  12  as a display device. The WebTV™ box  10  is coupled to the television set  12  by a video link  6 . The video link  6  is an RF (radio frequency), S-video, composite video, or other equivalent form of video link. The communication link  29  between the WebTV™ box  10  and the server  5  is either a telephone (POTS) connection  29   a  or an ISDN connection  29   b . The WebTV™ box  10  receives AC (alternating current) power through an AC power line  7 . 
     Remote control  11  is operated by the user in order to control the WebTV™ client  1  in browsing the Web, sending e-mail, and performing other Internet-related functions. The WebTV™ box  10  receives commands from remote control  11  via an infrared (IR) communication link. In alternative embodiments, the link between the remote control  11  and the WebTV™ box  10  may be RF or any equivalent mode of transmission. 
     FIG. 2B is a block diagram of the internal features of the WebTV™ box  10 . Operation of the WebTV™ client  1  is controlled by a central processing unit (CPU)  21  which is coupled to an Application-Specific Integrated Circuit (ASIC)  20 . The CPU  21  executes software designed to implement features of the present invention. ASIC  20  contains circuitry which may be used to implement certain features provided by the WebTV™ client  1 . ASIC  20  is coupled to an audio digital-to-analog converter  25  which provides audio output to television  12 . In addition, ASIC  20  is coupled to a video encoder  26  which provides video output to television set  12 . An IR interface  24  detects IR signals transmitted by remote control  11  and, in response, provides corresponding electrical signals to ASIC  20 . A standard telephone modem  27  and an ISDN modem  30  are coupled to ASIC  20  to provide connections  29   a  and  29   b , respectively, to the modem pool  2  and, via the Internet  3 , to the remote servers  4 . Note that the WebTV™ box  10  also may include a cable television modem (not shown). 
     Also coupled to ASIC  20  is Read-Only Memory (ROM)  22 , which provides storage of program code for implementing the application software to be executed by the WebTV™ box  10 . Note that ROM  22  may be a programmable ROM (PROM) or any form of erasable PROM (EPROM) or Flash memory. Also coupled to ASIC  20  is Random Access Memory (RAM)  23 . A mass storage device  28  may optionally be provided and coupled to ASIC  20 . The mass storage device  28  may be used to input software or data to the client or to download software of data received over network connection  29 . The mass storage device  28  includes any suitable medium for storing machine-executable instructions, such as magnetic disks, optical disks, and the like. 
     FIG. 3 illustrates a WebTV™ client  1  implemented in a home  15  according to one exemplary embodiment. Within the home  15 , the WebTV™ client  1  shares the telephone line  29   a  with two conventional telephone sets (“extensions”)  10  and a modem of a personal computer  12 . Accordingly, the telephone line  29   a  is used for both data communication (by WebTV™ client  1  and the personal computer  12 ) and voice communication at different times. The telephone line  29   a  corresponds to a single telephone number within the home  15 . 
     As mentioned above, the WebTV™ box  10  includes application software including a Web browser. Referring now to FIG. 2A, the above-mentioned application software  31  operates in conjunction with operating system (OS) software  32 . The OS software  32  includes various device drivers and otherwise provides an interface between the application software  31  and the system hardware components  40  (i.e., the elements illustrated in FIG.  1 C). 
     In the preferred embodiment, the application software  31  and OS software  32  are generally stored in ROM  22 . It will be recognized, however, that either or both of application software  31  and OS software  32  can be stored on any suitable storage medium, including magnetic or optical storage devices. 
     Assume now that the WebTV™ client  1  is implemented in a configuration as shown in FIG.  3 . That is, the WebTV™ client  1  shares a single telephone line  29   a  with one or more standard telephone extensions in a home  15 . Assume further that telephone service provided to the home  15  includes the Call Waiting and Caller ID services. Hence, an incoming telephone call received at the home  15  while the user is browsing the Web using the WebTV™ client  1  will be indicated by reception of a Call Waiting signal. The Call Waiting signal will cause disruptions in data communications on the telephone line. Some prior art client-to-server modems treat a disruption such as a Call Waiting signal as an error condition and either attempt to maintain the data connection or simply lose the connection. Other prior art client-to-server modems simply disable the Call Waiting signal. A disadvantage of both of these approaches is that the user of the Web browser is typically left unaware of the incoming call. The present invention, however, overcomes this disadvantage. 
     Any interruption in data communication is essentially treated as a pause condition by the WebTV™ client  1 . Specifically, in response to any interruption in data communication, including a Call Waiting signal, the client  1  automatically disconnects from the modem pool  2  and then automatically reconnects to the modem pool  2  at a later time while maintaining the user&#39;s browsing state. Referring now to FIG. 5, if an interruption in communication is detected by the WebTV™ client  1  (step  501 ) while the client  1  is in contact with the WebTV™ server  5  (or any other server), then the client  1  saves information describing the current browsing status to memory (RAM)  23  (step  502 ). The saved information includes all information that is necessary to exactly identify the Web site at which the user was browsing and to automatically return to that location later without further input from the user. Once the status information is saved, the client  1  automatically disconnects from the modem pool  2  (step  503 ). The client  1  then waits for a predetermined time interval T 1  (ten seconds, for example) (step  504 ). At the expiration of the time interval T 1 , the client  1  determines whether an incoming call is still being received by attempting to detect a ring signal on the telephone line  29  (step  505 ). Detection of a ring signal would indicate that a third party is still attempting to call in, since an on-hook condition after a Call Waiting signal tells the Telephone Company Central Office telephone switch that it is to transmit a ring signal. The client  1  further determines whether all telephone extensions are on the hook (i.e., inactive, or closed) (step  506 ). This determination is made by sensing the impedance on the telephone line  29 . If no ring signal is detected and all extensions are on the hook, then the client  1  automatically redials the modem pool  2  and resumes the previous browsing state based the status information saved earlier (step  507 ). If, however, either a ring signal is detected or an extension is off the hook (active) (e.g., if another member of the household had picked up an extension phone and had begun to dial), then the client  1  waits until that is not the case before re-establishing the connection to the modem pool  2 . Thus, whether the disruption was a Call Waiting interruption or a disruption from another person trying to make a call, the same mechanism gracefully handles the situation. 
     As mentioned above, it is assumed that the telephone service provided to the home  15  includes Caller ID service. Note, however, that Caller ID service is not essential to support the Call Waiting capabilities of the present invention. The present invention utilizes the Caller ID information to provide the user with information identifying the source of the incoming call. Referring now to FIG. 6, assume that an incoming telephone call is received while the user is browsing the Web. Accordingly, the client  1  disconnects from the modem pool  2  after saving browsing status information. The client  1  then causes a message to be displayed to the user on the television set  12  indicating that an incoming call is being received (step  601 ). The client then waits for Caller ID information. This information is typically is received between the first and second ring signal (step  601 ). If Caller ID information is received before the expiration of a preset time period, such as before the second ring signal (step  602 ), then the client  1  determines whether the phone number of the incoming call has previously been stored in memory  23  with a corresponding name (step  603 ). If so, the name corresponding to the source of the incoming call is retrieved from memory  23  and displayed to the user in conjunction with the Call Waiting message (step  604 ). If no Caller ID information is received or if there is no name corresponding to the incoming phone number stored in memory  23 , then a message is displayed to the user indicating that the name of the caller is unknown (step  608 ). If the user accepts the incoming call by picking up one of the telephone sets  10  within the predetermined number of rings, the routine ends (step  605 ). However, if the user does not accept the call, client  1  automatically answers the call. Specifically, the client  1  plays a recorded greeting to the caller (step  606 ) and then digitally records any message the incoming caller chooses to leave (step  607 ). The message left by the incoming caller is also played to the user of the client  1  in real time as it is recorded, using the speaker of the television set  12  for audio output. 
     Referring now to FIG. 7, the next time the client  1  connects to the Internet, the client  1  automatically sends a request to appropriate “White Pages” database servers for the name of the source of the last telephone call (step  701 ), assuming Caller ID information was received for that call. The request includes the telephone number provided by the Caller ID service. Such Web sites containing “White Pages” telephone directory information are well-known. The telephone directory Web site allows the accessing party to search based on a given telephone number or name. Accordingly, the client  1  automatically looks up the telephone number from the Caller ID information using the telephone directory Web site (step  702 ). If the telephone directory Web site locates the telephone number (step  703 ), then upon receiving the name, the client  1  stores the telephone number and the corresponding name in memory  23  for future use (step  704 ). Hence, each time in the future an incoming call is received from that telephone number, the name of the calling party is automatically retrieved from memory  23  and displayed to the user (FIG. 6, step  604 ). 
     The present invention also includes a selective forwarding feature by which the user of the client  1  is automatically notified via e-mail or telephone when an incoming telephone call is received from a specified source, even if the user is at a geographic location different from that of the client  1 . The user initially selects a message forwarding option and inputs an identity of a calling party to the client  1 . The identity may be specified in the form of a telephone number or a name. Number buttons on remote control  11  can be used to enter the digits of a telephone number. To enter alphabetical characters of a name, the user can select soft buttons within an image of a keyboard that is displayed on television set  12 . Alternatively, the characters can be entered through the use of a wireless keyboard. The user also selects a forwarding mode as either “e-mail,” “telephone,” or both and inputs a destination e-mail address and/or telephone number designating the location to which the forwarding message is to be sent. 
     FIG. 8 illustrates a routine by which the client  1  forward messages to the user at a remote location. When an incoming call is received, then if the user has selected the message forwarding option (step  801 ), the client  1  determines whether the calling party identity specified by the user matches the Caller ID information (step  802 ). If the user-specified identity was provided as a name, the client  1  uses the identification procedures described above to determine if there is a match. Specifically, the client  1  determines whether the telephone number in the Caller ID information is stored in memory  23  and, if so, whether there is a corresponding name stored. 
     If the Caller ID information does not match the user-specified caller identity, the standard routine for handling incoming calls is performed (step  805 ). If, however, there is a match, then the client  1  waits until the line is clear (i.e., no incoming call is being received and all handsets are on the hook) (step  803 ). When the line is clear, the client  1  automatically dispatches a message to the location specified by the user. The message may be a default message or a user-created message. If the telephone mode was selected, the client  1  will automatically dial the user-specified destination telephone number and play a pre-recorded message if the call is answered. Hence, using the above technique, the user is notified immediately when a specified party calls, even when the user is located away from the client  1 . 
     The present invention also provides conventional e-mail capabilities. E-mail addressed to a WebTV™ user is stored in the WebTV™ server  5 . When e-mail addressed to the user is received by the server  5 , the server  5  signals this fact to the client  1  if the client  1  is presently connected to the server  5 . Upon receiving this signal, the client  1  provides an indication to the user that the user has e-mail. The indication is provided in the form of a lighted LED (Light-Emitting Diode) built into the housing of WebTV™ box  10 , a text message displayed on television set  12 , or both. In one embodiment of the present invention, the client  1  automatically dials out and connects to the WebTV™ server  5  at regular intervals or at specified times of the day to determine whether the user has any new e-mail, and both downloads any e-mail into memory (e.g., RAM  23 ) for fast retrieval and illuminates the LED. 
     Another feature of the present invention relates to reducing costs associated with ISDN service. As mentioned above, the client  1  has both a standard telephone connection  29   a  and an ISDN connection  29   b  with the server  5 . It is well known that an ISDN connection permits faster data communication than a standard telephone connection according to the present state of the art. However, ISDN service tends to be more expensive than standard telephone service. Consequently, the present invention provides a means for reducing communications costs associated with accessing the Internet. Specifically, the client  1  keeps track of the time of day and routes communications through the ISDN connection  29   b  during hours which are not considered “prime time” for ISDN usage. However, the client  1  automatically directs communications through the standard telephone connection  29   a  during ISDN prime time, when rates are most expensive. 
     In another aspect of the present invention, the client  1  automatically disconnects from the WebTV™ server  5  when no input from the user is received for a predetermined period of time. The current browsing status is saved to memory  23  before disconnecting, as described above. The connection is automatically reestablished and the most recent browsing status is resumed as soon as the user enters any input which requires access to the network. Hence, the user is not required to initiate a specific log-in procedure in order to resume browsing. 
     Thus, a method is provided, in a client processing system coupled to a server processing system, of managing communications between the client and the server. Although the present invention has been described with reference to specific exemplary embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the invention as set forth in the claims. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.