Abstract:
A dual mode Internet telephone is capable of operating as a tone/pulse dial telephone as well as with the Internet by transmitting dual-tone multi-frequency (DTMF) tones in response to dialing. The dual mode telephone includes a mode control switch which is either manually selectable to permit a user to choose between making a call over a standard telephone network or over the Internet or is automatically controlled to route the call via the more advantageous communications link depending upon various factors and considerations. In the standard telephone mode of operation, most of the Internet telephony circuit is disabled and the dial/touchtone keypad, earpiece and mouthpiece, and ringer are connected to the telephone line. In the Internet mode of operation, dialed digits are stored and converted to Internet telephony call set-up messages. The signals to/from the earpiece and mouthpiece are digitized, compressed and packetized by a digital signal processor. A built-in modem connects the digital signal processor and the call control messages through the standard telephone line to the Internet Service Provider (ISP). A control processor manages the connections and drives the keypad and ringer. A non-volatile memory stores configuration data such as the ISP number(s) to call and various other features related to the Internet mode of operation. The memory can also be programmed with other operating parameters for use by the control processor in an automatic mode of operation to override the manual switch and automatically place or receive a call via either the standard telephone network or the Internet.

Description:
TECHNICAL FIELD 
     This invention relates generally to wireline communications systems and is particularly directed to a dual mode telephone capable of operating in either a standard telephone network or via the Internet. 
     BACKGROUND OF THE INVENTION 
     The cost per minute of Internet access is approaching, and may soon be less than, the cost per minute of long distance telephone service. As a result, increasing numbers of telecommunications users are using voice over the Internet to place toll calls rather than via a standard telephone network. The Internet provides acceptable voice quality at a cost much less than that of a traditional long distance call. 
     Using the Internet to make a phone call currently requires the user to initiate the call using a personal computer (PC) in combination with a modem to contact an Internet Service Provider (ISP). After initially contacting the ISP, the user must then go through a complex log-on process to gain access to the Internet. Once logged on, the user must then employ an Internet telephony software package in entering the number to be called. The network of the ISP then connects the user to the called party via the Internet. Many potential Internet telephony users find the complexity of this procedure unacceptable and refuse to use the Internet in this communications context in favor of the more familiar, traditional long distance telephone service. In addition, even after the user goes through the complex procedure to establish an Internet telecommunications link, communication via the Internet is not entirely reliable may not be possible for any of several reasons. For example, all ISP ports may be busy or there may be insufficient connection bandwidth available to the desired destination. 
     There are also available single mode, digital phones having access to the Internet via a Local Area Network (LAN). This is also not a particularly reliable communications link because of the limited availability of the LAN which is typically shared by a large number of users. 
     The present invention addresses the aforementioned limitations of the prior art by providing a dual mode Internet telephone have a selectable mode switch which is capable of communicating either via a standard toll telephone network or via the Internet and which automatically reverts to the standard toll telephone network operation when Internet telephony is not available. 
     SUMMARY OF THE INVENTION 
     This invention contemplates a dual mode Internet telephone with a mode control switch either of the manual type or which is processor controlled. The operation of the dual mode telephone is conceptually similar to current tone/pulse dialed telephones, where the user is able to control whether dial pulses or Dual Tone Multi-Frequency (DTMF) tones are sent in response to dialing. The inventive dual mode phone includes a Standard/Internet Mode Switch that allows the user to choose between making the call over a standard telephone network or via the Internet. A programmed processor may also be used to automatically control the mode of the switch. In the standard mode of operation, most of the advanced Internet telephony circuitry in the phone is disabled, and the dial/touchtone keypad, earpiece and mouthpiece, and ringer are connected to the metallic telephone line as in a standard telephone network. In the Internet mode of operation, when the user goes off hook, a connection is automatically established to a pre-programmed Internet Service Provider (ISP) number(s). The dialed digits are stored and converted to Internet telephony call set-up messages. The signals to/from the earpiece and mouthpiece are digitized, compressed and packetized by a digital signal processor. A built-in modem connects the digital signal processor and the call controlled messages through the standard telephone line to the ISP. A control processor manages the connections, and drives the keypad and ringer. A nonvolatile memory stores configuration data such as the ISP number(s) to call, and various Internet mode control information. The mode control switch may be automatically controlled by logic within the control processor which takes into consideration such information as the dialed digits, time of day, and other factors to determine if it is most advantageous to complete the call over the Internet or via the standard telephone network. Provision is made for the user to override the automatic selection of mode of communication. The dual mode Internet telephone can receive calls via the standard telephone network or the Internet. If the ISP is attempting to complete a connection to a subscriber with the inventive dual-mode telephone, the ISP calls the user&#39;s directory number and, based on detecting the caller ID of the ISP, the dual mode Internet telephone configures itself to an Internet mode, picks up the line and establishes a connection. The user then receives a distinctive ring and has the option to pick up the receiver and answer the call. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The appended claims set forth those novel features which characterize the invention. However, the invention itself, as well as further objects and advantages thereof, will best be understood by reference to the following detailed description of a preferred embodiment taken in conjunction with the accompanying drawings, where like reference characters identify like elements throughout the various figures, in which: 
     FIG. 1 is a simplified combined block and schematic diagram of a dual mode telephone system in accordance with the principles of the present invention; 
     FIGS. 2 a  and  2   b  are simplified flowcharts illustrating the steps carried out by means of a control processor in the dual mode telephone of the present invention in placing an outgoing call either via a standard telephone network or over the Internet; and 
     FIGS. 3 a  and  3   b  are simplified flowcharts illustrating the steps carried out in receiving an incoming call either via a standard telephone network or over the Internet in accordance with another aspect of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring FIG. 1, there is shown a simplified combined block and schematic diagram of a dual mode telephone  10  in accordance with the principles of the present invention. The dual mode telephone  10  is connected to a Plain Old Telephone System (POTS) line  12  by means of a mode control switch  14 . The mode control switch  14  is a two-position switch allowing the dual mode telephone  10  to be connected to either a standard telephone network or to a global information network such as the Internet. In a preferred embodiment, mode control switch  14  is in the form of a relay  15  having contacts which are normally closed. When relay  15  is not energized, relay  15  connects the POTS line  12  to a standard telephone line  16  for use in a standard mode of operation as shown in FIG.  1 . When relay  15  is energized, relay  15  connects the POTS line  12  to an Internet line  18 . In the event of a power supply failure, the relay  15  is de-energized and the telephone automatically operates via the standard telephone line  16 . Mode control switch  14  is controlled either manually by a user of the dual mode telephone  10  or automatically by means a control processor  22  as described in detail below. In the manual mode of operation, either a standard mode button  17  connected to the control processor  22  for communicating via a standard telephone network or an Internet mode button  19  also connected to the control processor for communicating via the Internet is selected. In a preferred embodiment, the manual setting of the model control switch  14  can be overridden by the control processor  22  based upon data stored in a configuration memory  28 . The configuration memory  28 , which is a preferred embodiment is of the nonvolatile type, stores various system operating parameters and configuration data for use by the control processor  22  for automatically controlling the operation of the dual mode telephone  10 . A ringer circuit  24  is connected to a standard telephone line  16  and operates in a conventional manner when actuated via the standard telephone line. Ringer circuit  24  is also coupled to and controlled by the control processor  22  when in the Internet mode of operation as described below. The standard telephone line  16  is connected to a conventional telephone hybrid circuit  32  which, in turn, is connected to an earpiece  38  and a mouthpiece  40  as is conventional. Hybrid circuit  32  is typically in the form of a network including resistors, capacitors and a low voltage transformer and has a first pair of leads connected to the standard telephone line  16  and second and third pairs of leads respectively connected to the earpiece  38  and mouthpiece  40 . A keypad  30  is connected and provides inputs to the control processor  22  as well as DTMF signals to the hybrid circuit  32 . The hybrid circuit  32  provides output signals for driving the earpiece  38  and receives outputs from the mouthpiece  40  for providing these audio signals to the standard telephone line  16 . Also included in the dual mode telephone  10  is a two position switch hook  36 . The ringer circuit  24 , keypad  30 , hybrid circuit  32  and the combination of earpiece  38  and mouthpiece  40  are standard components in a conventional telephone. When the dual mode telephone  10  of the present invention operates in the telephone mode of operation using the standard telephone line  16 , these components operate in a manner similar to their operation in a conventional telephone. When the dual mode telephone  10  operates in the Internet mode of operation, these components operate under the control of the control processor  22  as described in detail below. 
     For use in the Internet mode of operation, the dual mode telephone  10  further includes a modem/caller identification (ID) unit  20  and a digital signal processor (DSP)  26 . The modem/caller ID unit  20  allows Internet calls to be placed using a local telephone line to an Internet Service Provider (ISP). The caller ID provides for the situation where a user of the dual mode telephone  10  is engaged in a telephone call using the standard telephone line  16  and an incoming call is received via the Internet. The caller ID also detects the source of incoming calls and can determine whether an incoming call is from an ISP. The caller ID provision allows the user to decide whether to interrupt the call on the standard telephone line and accept the call from the Internet, or to continue the call on the standard telephone line. The DSP  26  provides for digitizing, compressing and packatizing signals to/from the earpiece  38  and mouthpiece  40 . DSP  26  may also include a security provision for encrypting/de-encrypting the signals transmitted via the Internet. Earpiece  38  and mouthpiece  40  are connected to the DSP  26  by means of a coder/decoder (CODEC)  34 . CODEC  34  converts the digital signals output by the DSP  26  to analog signals for use by earpiece  38 . CODEC  34  also converts the analog signals output by the mouthpiece  40  to digital signals for use by the DSP  26 . DSP  26  decompresses the digital signals from the CODEC  34  prior to providing these signals to the modem/caller ID  20 . For example, CODEC  34  typically provides pulse code modulated (PCM) signals at the rate of 64 kbps to the DSP  26 , with the DSP then compressing these digital signals to 5-32 kbps which is then provided to the modem/caller ID  20 . The output of the DSP  26  to the modem/caller ID  20  is in the form of messages compatible with the Internet Protocol (IP). DSP  26 , on the other hand, decompresses the digital signals output by the modem/caller ID  20  prior to providing these signals to the CODEC  34 . Components which could be used in the dual model telephone  10  include the following: for the control processor  22 , an 8051 Intel signal chip microprocessor; for the modem/caller ID  20 , a standard V90 modem chip set such as available from Lucent Technologies, Inc. or Rockwell International, Inc.; and DSP  26  could be in the form of a Lucent Technologies 1610 or Texas Instruments 548 digital signal processor. 
     The configuration memory  28  may be programmed with various information relating to the standard telephone network as well as to the Internet for completing telephone calls via either communications link. Examples of information which could be stored in the configuration memory  28  for recall and use by the control processor  22  would include an Internet user ID number, a password for Internet access, and the telephone number of the ISP, as well as any alternate numbers for other ISP&#39;s when the primary ISP number is busy. In addition, it may be desirable to place all calls to certain numbers via either the standard telephone network or via the Internet. In this case, a number dialed using keypad  30  would be compared by the control processor  22  with numbers stored in the configuration memory  28  for automatically routing the dialed number via either the standard telephone network or via the Internet. It may also be desirable to automatically route calls made at a certain time of the day, on a certain day of the week, or to certain designated area codes via the Internet. This automatic call routing is accomplished by the control processor  22  which reads this information from the configuration memory  28  and automatically routes the call via either the standard telephone network or via the Internet. It may also be desirable during a call on the standard telephone network to automatically switch to an incoming call on the Internet for certain calling numbers. This, too, would be accomplished by the control processor  22  in accordance with data stored in the configuration memory  28 . This type of operating and control data could be stored in the configuration memory  28  by appropriate entries on keypad  30  using the control processor  22 . 
     Referring to FIGS. 2 a  and  2   b , there are shown simplified flowcharts illustrating the steps carried out by means of the control processor  22  in the dual mode telephone  10  in placing an outgoing call either via a standard telephone network or over the Internet in accordance with one aspect of the present invention. In these flowcharts, a rectangular symbol represents an instruction or set of instructions resulting in the performance of a control function, while a diamond indicates a decision point based upon the comparison of binary signal inputs. An oval represents the start of an operation, while a circular symbol represents the transition between consecutive flowcharts in carrying out a sequence of steps in accordance with the present invention. The steps represented in the flowcharts are carried out by means of a program stored in the control processor  22  which writes data into and reads data from the configuration memory  28  in controlling the operation of the various components of the dual mode telephone  10  shown in FIG. 1 as described below. 
     An outgoing call is initiated at step  50  when the telephone handset is placed off hook. Following detection of a handset off hook condition, the program stored in the control processor  22  proceeds to step  52  and checks for the status of the mode control switch  14 . If the mode control switch  14  is determined at step  52  to be in the standard mode of operation, the program branches to step  54  and connects the analog POTS line  12  to the hybrid circuit  32  at step  54 . The program then proceeds to step  56  and connects the outgoing call via the hybrid  32  and mode control switch  14  to the POTS line  12 . 
     If at step  52 , it is determined that the mode control switch  14  is in the Internet mode, the program branches to step  58  and collects the dialed digits entered by the user via the keypad. The program then proceeds to step  60  and analyzes the dialed digits, followed by a determination at step  62  if the call should be transmitted over the Internet. This analysis of the dialed digits would typically involve a comparison of the dialed digits with telephone numbers stored in and read from the configuration memory  28  by the control processor  22 . If it is determined at step  62  that the call is not to be transmitted via the Internet, the program branches to step  64  and dual-tone multi-frequency tones are generated by the DSP  26  and transmitted through the modem/caller ID unit  20  to the POTS line  12  via the mode control switch  14 . The dual mode telephone  10  is then connected to the POTS line  12  through the hybrid circuit  32  for directing the call to the standard telephone network. 
     If at step  62 , it is determined that the call is to be transmitted via the Internet, the program at step  66  then accesses the POTS line  12  by executing a line off hook operation. The program then dials the number of the designated Internet service provider (ISP) through the modem/caller ID  20  at step  68 . The designated ISP telephone number is stored in the configuration memory  28  and is automatically dialed by means of the control processor  22  for accessing the ISP. If a busy signal is detected at step  70 , the program hangs up the dual mode telephone  10  at step  72  and, after a predetermined time period, dials the ISP alternate number at step  74  and continues this process until a busy signal is not received and a call is placed to the ISP. The program then waits for an answer at step  76 . When the call is answered at the ISP, the program then transmits the user identification (ID) number and an Internet password at step  78 . This information is stored in the configuration memory  28  and is read from the memory by the control processor  22 . The program then at step  80  waits for a login on the Internet. After an Internet login occurs, the program at step  82  requests an Internet Protocol (IP) telephony session. At step  84 , the program then transmits the collected digits of the called number and determines at step  86  if a normal connection has been established with the Internet. If at step  86  a normal connection to the Internet is not detected, the program then plays an error message  88  over the dual mode telephone&#39;s earpiece  38  at step  88 . The error message may be programmed into the DSP  26  and played back to the user in the event a normal Internet connection is not established. The error message may be in the form of a tone, or a series of tones, or may be a voice message. Failure to establish a normal connection with the Internet may be due to a line to the ISP being busy, the caller not being properly logged in, or an overloaded backbone on the Internet. Following playing of the error message to the user at step  88 , the program then attempts again at step  90  to call the desired number, but this time via the analog POTS line  12 . If the attempted call is not established via the POTS line  12 , the program stored in the control processor  22  terminates the outgoing call procedure at step  92 . If contact with the desired number is established via the analog POTS line at step  90 , the program then branches back to step  64  with the modem/caller ID  20  providing the DTMF digits to the, POTS line  12 . Connection to the dialed number is then established at step  56  through the hybrid circuit  32  via the POTS line  12 . 
     If at step  86  normal connection is established with the ISP, the program proceeds to step  94  and initializes the DSP  26 . After the DSP  26  is initialized, the program then connects the CODEC  34  at step  96  with the earpiece  38  and mouthpiece  40 . The program then at step  98  initiates the IP telephony session. The program continues with the IP telephony session at step  98  until either a handset on hook is detected for the local call at step  100  or a loss of the IP connection is detected at step  102 . In the latter case, an IP lost connection is due to either a called party or a network error. Following either the detection of a handset on hook or a loss of the IP connection, the program then terminates the IP telephony session at step  104  followed by the transmission of a logoff sequence at step  106 . The POTS line is then placed on hook at step  108  followed by the end of the outgoing call routine at step  110 . The handset on hook signal is provided to the control processor  22  from a handset-coupled switch hook  36 . 
     Referring to FIGS. 3 a  and  3   b , there are shown flowcharts illustrating the steps carried out by the control processor  22  in the case of an incoming call to the dual mode telephone of the present invention. The incoming call routine is initiated at step  120  followed by the detection of a line ringing signal at step  122 . Following detection of a line ringing signal, the program then collects the caller ID at digits at step  124  and then at step  126  determines if the calling number corresponds to the number of an ISP. A comparison is made here by the control processor  22  of the calling member with ISP numbers stored in the configuration memory  28 . If the calling number does not correspond with the number of an ISP, the program branches to step  128  and initiates ringing of the dual mode telephone in the analog mode with the received call transmitted via the POTS line  12 . If at step  126 , it is determined that the calling number corresponds to an ISP number, the program then initiates the Internet mode of operation by placing the line off hook at step  130 . The dual mode telephone then places a modem carrier signal on the POTS line  12  at step  132  and the control processor  22  negotiates an Internet connection for the incoming call at step  134 . In negotiating the Internet connection, such system parameters as data rates, echo cancellation and signal compression are taken into consideration by the control processor  22  using data stored in the configuration memory  28 . Login messages are then accepted at step  136  by verifying the ISP with data stored in the configuration memory  28 . The program then checks to determine if the login is valid at step  138 , and if it is determined that the login is not valid, the program branches to step  140 , places the line on hook, and returns to the start of the program to detect if the line is ringing at step  122 . The line on hook operation is performed by a relay (not shown) in the modem/caller ID  20 . If at step  138 , it is determined that the login is valid, the program proceeds to step  142  for initiating the start of an IP telephony session. The calling party ID is then collected over the IP connection at step  144 , followed by a decision to either accept or reject the call at step  146 . The decision to accept the call at step  146  is based upon a comparison by the control processor  22  of the calling number with pre-programmed directory numbers stored in the configuration memory  28 . If the call is not accepted at step  146 , the program branches to step  140  and places the line on hook, followed by a return to step  122  for detection of a line ringing signal. Receipt of a call over the Internet may be indicated to a user by providing a distinctive ring at the receiving telephone. If at step  146  the call is accepted, the program initializes the DSP at step  148  and connects the CODEC with the earpiece  38  and mouthpiece  40  at step  150 . A distinctive line ringing signal identifying the call as received via the Internet is then provided at the receiving telephone by means of a ringer circuit at step  151 . The program then at step  153  waits for the call to be answered, i.e., for the telephone receiver to be picked up. The program then at step  152  initiates the IP telephony session at step  152 . The IP telephony continues until either the handset on hook is detected locally at step  154  or the IP connection is lost as detected at step  156 . Once the handset on hook is detected or the IP connection is lost, the program then proceeds to step  158  and terminates the IP telephony session followed by the sending of an Internet logoff sequence at step  160 . The program then places the line on hook at step  162 , followed by the end of the incoming call routine at step  164 . 
     While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention. The matter set forth in the foregoing description and accompanying drawing is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.