Telecommunication display system

• US 5,365,577 A
• Filed: 05/01/1992
• Issued: 11/15/1994
• Est. Priority Date: 09/27/1990
• Status: Expired due to Term

• Current Assignee: Rocket Software Incorporated
• Original Assignee: Radish Communications Systems, Inc. (SystemSoft Corp.)
• Inventors: Mathys, Peter, Witmore, Ronald K., Fette, Charles J., Davis, Richard A., Brittain, Anthony J.
• Primary Examiner(s): Chan, Wing F.
• Application Number:
  US07/877,328
• Time in Patent Office: 928 Days
• Field of Search: 379/90, 379/91, 379/93, 379/96-98, 379/100, 379/53, 379/54, 375/8, 375/13, 358/85, 348/14, 348/15, 348/17, 348/18
• US Class Current: 379/93.17
• CPC Class Codes: H04L 65/1094 Inter-user-equipment sessions transfer or sharing
• CPC Class Codes: H04L 65/401 wherein the services involve a main real-time session and one or more additional parallel real-time or time sensitive sessions, e.g. white board sharing or spawning of a subconference
• CPC Class Codes: H04M 1/6505 storing speech in digital form
• CPC Class Codes: H04M 11/066 Telephone sets adapted for data transmision
• CPC Class Codes: H04M 11/085 using a television receiver, e.g. viewdata system
• CPC Class Codes: H04M 3/51 Centralised call answering arrangements requiring operator intervention , e.g. call or contact centers for telemarketing
• CPC Class Codes: H04M 3/527 Centralised call answering arrangements not requiring operator intervention
• CPC Class Codes: H04M 3/533 Voice mail systems
• CPC Class Codes: H04N 19/90 using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals
• CPC Class Codes: H04N 21/8586 by using a URL processing chained hypermedia data for information retrieval G06F16/94; information retrieval from the Internet by using URLs G06F16/955; URL in broadcast information H04H20/93; Web-based protocols H04L67/02
• CPC Class Codes: H04Q 2213/13072 Sequence circuits for call signaling, ACD systems
• CPC Class Codes: H04Q 2213/13093 Personal computer, PC
• CPC Class Codes: H04Q 2213/13175 Graphical user interface [GUI], WWW interface, visual indication
• CPC Class Codes: H04Q 2213/13376 Information service, downloading of information, 0800/0900 services
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

A telecommunication system provides voice and data communications over a conventional telephone line that can be dynamically switched from voice mode to data mode during a single conversation. Each station includes a telephone for voice communications and bypass relay means for selectively connecting the telephone to the telephone line in voice mode and disconnecting the telephone while operating in data mode. Prior to transmitting data, the originating station first transmits a start signal over the telephone line that includes a rate signal indicating one of the several possible data transmission rates. If a station detects a start signal transmitted by a remote station, a microcontroller directs the bypass relay means and modem to automatically switch from voice mode to data mode in preparation for receiving data from the originating station.

Claims

1. A telecommunication system for bidirectional communication of voice and visual data via a plain old telephone system (POTS) connection, comprising:

an agent station having;

(a) agent visual data generating means for generating agent visual data;

(b) agent visual data display means for displaying visual data;

(c) an agent telephone;

(d) agent modem means for;

(1) transmitting visual data from said agent visual data generating means into said POTS, including tone generator means for generating signal tones on said POTS associated with said agent visual data including a start tone to indicate that visual data is about to be transmitted, flag signals, and rate signals to indicate the rate at which said visual data will be transmitted on said POTS; and

(2) receiving visual data from said POTS and transmitting it to said agent visual data display means, including tone detector means for detecting the start tone, flag signals and rate signals associated with said visual data received from said POTS;

(e) agent directional coupler means positioned between said POTS, said agent telephone, and said agent modem means for transmitting signals bidirectionally between said POTS and said agent telephone, for transmitting signals from said POTS to said agent modem means, and for inhibiting signal transfer between said agent telephone and said agent modem means;

(f) agent by-pass relay means positioned between said POTS and said agent directional coupler means for connecting and disconnecting said agent directional coupler and said agent telephone to and from said POTS; and

(g) agent microcontroller means for actuating said agent by-pass relay means to disconnect said agent telephone from said POTS in response to being signalled by said agent modem means that a start tone has been received, and for responding to said rate signals received by said agent modem means by generating signals to set said agent modem means to receive data at the rate indicated by said received rate signals, and then reconnecting said agent telephone to said POTS after said visual data has been received; and

a subscriber station having;

(a) subscriber visual data generating means for generating subscriber visual data;

(b) subscriber visual data display means for displaying visual data;

(c) a subscriber telephone;

(d) subscriber modem means for;

(1) transmitting subscriber visual data from said subscriber visual data generating means into said POTS, including tone generator means for generating subscriber signal tones on said POTS associated with said subscriber visual data including a subscriber start tone to indicate that visual data is about to be transmitted, subscriber flag signals, and subscriber rate signals to indicate the rate at which said subscriber visual data will be transmitted on said POTS; and

(2) receiving agent visual data from said POTS and transmitting it to said subscriber visual data display means, including tone detector means for detecting the agent start tone, agent flag signals and agent rate signals associated with said agent visual data received from said POTS;

(e) subscriber directional coupler means positioned between said POTS, said subscriber telephone, and said subscriber modem means for transmitting signals bidirectionally between said POTS and said subscriber telephone, for transmitting signals from said POTS to said subscriber modem means, and for inhibiting signal transfer between said subscriber telephone and said subscriber modem means;

(f) subscriber by-pass relay means positioned between said POTS and said subscriber directional coupler means for connecting and disconnecting said subscriber directional coupler and said subscriber telephone to and from said POTS; and

(g) subscriber microcontroller means for actuating said subscriber by-pass relay means to disconnect said subscriber telephone from said POTS in response to being signalled by said subscriber modem means that said agent start tone has been received, and for responding to said agent rate signals received by said subscriber modem means by generating signals to set said subscriber modem means to receive data at the rate indicated by said agent rate signals, and then reconnecting said subscriber telephone to said POTS after said agent visual data has been received.

2. The telecommunication system of claim 1, wherein said agent modem means is set up to receive and demodulate said subscriber visual data and to send demodulated visual data to said agent microcontroller means, and wherein said agent microcontroller means is programmed to receive said demodulated subscriber visual data, to form the demodulated subscriber visual data into sets, and to transmit the sets of demodulated subscriber visual data to said agent visual data display means, and to recognize the end of a transmission of subscriber visual data.

3. The telecommunication system of claim 1, wherein said agent station further comprises agent local disconnect relay means positioned between said agent directional coupler means and said agent telephone for connecting and disconnecting said agent directional coupler means to and from said agent telephone, wherein said agent local disconnect relay means is connected to said agent microprocessor means, and wherein said agent microprocessor means is programmed to actuate said agent local disconnect relay means to disconnect said agent directional coupler means from said agent telephone in response to said subscriber start tone on said POTS.

4. The telecommunication system of claim 3, wherein said agent station further comprises agent local power supply/tone generator means connected to said agent local disconnect relay means for providing local power and local audio tone to said agent telephone when said agent local disconnect relay means is actuated to disconnect said agent telephone from said POTS.

5. The telecommunication system of claim 4, wherein said agent station includes agent high pass filter means positioned between said agent directional coupler means and said agent modem means for establishing a low frequency limit and for blocking frequencies lower than said low frequency limit from reaching said agent modem means.

6. The telecommunication system of claim 5, wherein said agent station includes agent limiter means for establishing a high amplitude limit and for prohibiting signal amplitudes high than said high amplitude limit from reaching said agent modem means.

7. The telecommunication system of claim 6, wherein said agent modem means includes agent automatic gain control means positioned between said agent limiter means and said agent tone detector means for adjusting amplitude of signals within limits acceptable to said agent tone detector means.

8. The telecommunication system of claim 7, wherein said agent station includes agent isolation relay means connected to said agent microcontroller means and positioned between said agent directional coupler means and said agent high pass filter means for isolating said agent modem means from said agent directional coupler means, said agent microcontroller means being programmed to actuate said agent isolation relay means to isolate said agent modem means from said agent directional coupler means when said subscriber start tone is detected on said POTS.

9. The telecommunication system of claim 8, wherein said agent station includes agent summing means positioned between said agent high pass filter means and said agent limiter means and between said agent by-pass relay means and said agent limiter means for connecting said agent modem means to said agent by-pass relay means, and for summing the signal output by said agent modem means with the output of said agent high pass filter means.

10. The telecommunication system of claim 9, wherein said agent by-pass relay means has a default mode in which said agent directional coupler means is connected to said POTS when said agent by-pass relay means is not powered, and wherein said agent local disconnect relay means has a default mode in which said agent telephone is connected to said agent directional coupler means when said agent local disconnect relay means is not powered.

11. The telecommunication system of claim 10, wherein said agent isolation relay means has a default mode in which said agent modem means is connected to said agent directional coupler means when said agent isolation relay means is not powered.

12. The telecommunication system of claim 11, wherein said agent modem means includes agent data transmitting means for transmitting an agent acknowledgement signal to said subscriber station upon receipt of said subscriber visual data by said agent station.

13. The telecommunication system of claim 1, wherein said subscriber modem means detects a telephone ring signal on said POTS and goes off-hook and said subscriber station further comprises memory means for receiving and storing said agent visual data for later delivery to said subscriber visual data display means.

14. The telecommunication system of claim 1, including an automatic answering and voice recording machine connected to said subscriber telephone for automatically going off-hook in response to a telephone ring signal on said POTS and for recording voice communications on said POTS.

15. A telecommunication system for sequentially transmitting voice and visual communications via a plain old telephone system (POTS) connection, comprising:

an agent station having;

(a) agent visual data generating means for generating agent visual data;

(b) agent transfer means connected to said agent visual data generating means for transmitting said agent visual data into said POTS; and

(c) agent tone generator means for generating signal tones on said POTS associated with said agent visual data including;

(1) an agent start tone to indicate that agent visual data is about to be transmitted;

(2) agent flag signals; and

(3) agent rate signals to indicate the rate at which said agent transfer means will transmit said agent visual data on said POTS; and

a subscriber station having;

(a) subscriber visual data display means for displaying agent visual data from said agent station;

(b) a subscriber telephone;

(c) subscriber modem means for receiving said agent visual data and transmitting it to said subscriber visual data display means, and including means for detecting said agent start tone, said agent flag signals and said agent rate signals;

(d) subscriber directional coupler means positioned between said POTS, said subscriber telephone, and said subscriber modem means for transmitting signals bidirectionally between said POTS and said subscriber telephone, for transmitting signals from said POTS to said subscriber modem means, and for inhibiting signal transfer between said subscriber telephone and said subscriber modem means;

(e) subscriber by-pass relay means positioned between said POTS and said subscriber directional coupler means for connecting and disconnecting said subscriber directional coupler and said subscriber telephone to and from said POTS; and

(f) subscriber microcontroller means for actuating said subscriber by-pass relay means to disconnect said subscriber telephone from said POTS in response to being signalled by said subscriber modem means that said agent start tone has been received, and for responding to said agent rate signals received by said subscriber modem means by generating signals to set said subscriber modem means to receive data at the rate indicated by said agent rate signals, and then reconnecting said subscriber telephone to said POTS after said agent visual data has been received.

16. The telecommunication system of claim 15, wherein said subscriber modem means is set up to receive and demodulate said agent visual data and to send demodulated visual data to said subscriber microcontroller means, and wherein said subscriber microcontroller means is programmed to receive said demodulated agent visual data, to form the demodulated agent visual data into sets, to transmit the sets of demodulated agent visual data to said subscriber visual data display means, and to recognize the end of a transmission of agent visual data.

17. The telecommunication system of claim 15, wherein said subscriber station further comprises subscriber local disconnect relay means positioned between said subscriber directional coupler means and said subscriber telephone for connecting and disconnecting said subscriber directional coupler means to and from and said subscriber telephone means, and wherein said subscriber local disconnect relay means is connected to said subscriber microprocessor means and said subscriber microprocessor means is programmed to actuate said subscriber local disconnect relay means to disconnect said subscriber directional coupler means from said subscriber telephone in response to said agent start tone on said POTS.

18. The telecommunication system of claim 17, wherein said subscriber station further comprises subscriber local power supply/tone generator means connected to said subscriber local disconnect relay means for providing local power and local audio tone to said subscriber telephone when said subscriber local disconnect relay means is actuated to disconnect said subscriber telephone from said POTS.

19. The telecommunication system of claim 17, wherein said subscriber by-pass relay means has a default mode in which said subscriber directional coupler means is connected to said POTS when said subscriber by-pass relay is not powered, and wherein said subscriber local disconnect relay means has a default mode in which said subscriber telephone is connected to said subscriber directional coupler means when said subscriber local disconnect relay means is not powered.

20. The telecommunication system of claim 15, further comprising subscriber limiter means for establishing a high amplitude limit and for prohibiting signal amplitudes higher than said high amplitude limit from reaching said subscriber modem means.

21. The telecommunication system of claim 20, wherein said subscriber modem means includes subscriber automatic gain control means positioned between said subscriber limiter means and said subscriber tone detector means for adjusting amplitude of signals within limits acceptable to said subscriber tone detector means.

22. The telecommunication system of claim 15, further comprising subscriber high pass filter means positioned between said subscriber directional coupler means and said subscriber modem means for establishing a low frequency limit and for blocking frequencies lower than said low frequency limit from reaching said subscriber modem means.

23. The telecommunication system of claim 22, wherein said subscriber transfer means includes subscriber isolation relay means connected to said subscriber microcontroller and positioned between said subscriber directional coupler means and said subscriber high pass filter means for isolating said subscriber modem means from said subscriber directional coupler means, said subscriber microcontroller being programmed to actuate said subscriber isolation relay means to isolate said subscriber modem means from said subscriber directional coupler means when said agent start tone is detected on said POTS.

24. The telecommunication system of claim 23, wherein said subscriber isolation relay means has a default mode in which said subscriber modem means is connected to said subscriber directional coupler means when said subscriber isolation relay means is not powered.

25. The telecommunication system of claim 15, wherein said start tone has a duration of about 200 milliseconds.

26. The telecommunication system of claim 15, wherein said subscriber modem means includes subscriber data transmitting means for transmitting a subscriber acknowledgement signal to said agent station upon receipt of said agent visual data by said subscriber station.

27. The telecommunication system of claim 15, wherein said agent transfer means includes:

agent modem means for modulating said agent visual data from said agent visual data generating means and sending the modulated visual data into said POTS, for modulating said agent flag signals and sending said agent flag signals into said POTS, and for generating tones for use as said agent start tone and for use as said agent rate signals; and

agent microcontroller means connected to said agent modem means for generating said agent flag signals, for controlling actuation and deactuation of said agent modem means to modulate and send said agent flag signals, and for controlling actuation and deactuation of said agent modem means to generate and send said agent start tone and said agent rate signals.

28. The telecommunication system of claim 27, wherein said agent modem means includes first agent tone generator means for producing a tone having a first frequency and second agent tone generator means for producing a tone having a second frequency, and wherein said subscriber modem means includes first subscriber tone detector means for detecting a tone having said first frequency and second subscriber tone detector means for detecting a tone having said second frequency.

29. The telecommunication system of claim 28, wherein said agent microcontroller means is programmed to actuate said first agent tone generator and said second agent tone generator simultaneously to produce simultaneous tones having said first frequency and said second frequency, respectively, to comprise said agent start tone.

30. The telecommunication systems of claim 28, wherein said first frequency and said second frequency are both in the range of about 300 to 3,300 Hz.

31. The telecommunication system of claim 28, wherein said first frequency is about 2,312.5 Hz.

32. The telecommunication system of claim 28, wherein said second frequency is about 2,912.5 Hz.

33. The telecommunication system of claim 27, wherein said flag signal includes six bytes of data.

34. The telecommunication system of claim 27, wherein a byte of said flag signal comprises a 01111110 byte.

35. The telecommunication system of claim 27, wherein said agent microcontroller means is programmed to actuate said agent modem means to modulate and transmit data after said agent modem means produces said agent start tone and then sequentially to produce said agent flag signal for modulation and transmission by said agent modem means.

36. The telecommunication system of claim 27, wherein said agent modem means and said subscriber modem means both have selectable low, medium, and high data transmitting and receiving rates.

37. The telecommunication system of claim 36, wherein said low data transmitting and receiving rate is about 300 bits per second.

38. The telecommunication system of claim 36, wherein said medium data transmitting and receiving rate is about 4,800 bits per second.

39. The telecommunication system of claim 36, wherein said high data transmitting and receiving rate is about 9,600 bits per second.

40. The telecommunication system of claim 36, wherein said agent microcontroller is programmed to actuate said agent modem means for transmitting said agent flag signals at said low rate.

41. The telecommunication system of claim 40, wherein said subscriber microcontroller means is programmed to actuate said subscriber modem means to receive and demodulate data in response to said agent start signal.

42. The telecommunication system of claim 41, wherein said subscriber microcontroller means is programmed to actuate said subscriber modem means to receive and demodulate data at said low rate in response to said agent start signal.

43. The telecommunication system of claim 42, wherein said agent microcontroller means is programmed to reconfigure said agent modem means after said agent flag signals are transmitted to produce and transmit said agent rate signal on said POTS.

44. The telecommunication system of claim 43, wherein said subscriber microcontroller means is programmed with a time limit and is programmed to determine whether said agent rate signal is received by said subscriber modem means within said time limit from when said subscriber microcontroller means reconfigures said subscriber modem means to actuate first and second subscriber tone detector means and, if not, to return said subscriber station to a voice mode by outputting signals to actuate said subscriber by-pass relay means, said subscriber local disconnect relay means, and said subscriber isolation relay means to reconnect said subscriber telephone to said POTS, to disconnect said subscriber visual data receiving means from said POTS, and to disconnect said subscriber local power supply/tone generator means from said subscriber telephone.

45. The telecommunication system of claim 41, wherein said subscriber microcontroller means is programmed with a time limit and is programmed to determine whether said agent flag signals are received by said subscriber modem means within said time limit from when said subscriber microcontroller means reconfigures said subscriber modem means to receive data and, if not, to return said subscriber station to a voice mode by outputting signals to actuate said subscriber by-pass relay means, said subscriber local disconnect relay means, and said subscriber isolation relay means to reconnect said subscriber telephone to said POTS, to disconnect said subscriber visual data receiving means from said POTS, and to disconnect said subscriber local power supply/tone generator means from said subscriber telephone.

46. The telecommunication system of claim 15, wherein said subscriber modem means detects a telephone ring signal on said POTS and goes off-hook and said subscriber station further comprises memory means for receiving and storing said agent visual data for later delivery to said subscriber visual data display means.

47. The telecommunication system of claim 15, including an automatic answering and voice recording machine connected to said subscriber telephone for automatically going off-hook in response to a telephone ring signal on said POTS and for recording voice communications on said POTS.

48. The telecommunication system of claim 15, wherein said subscriber visual display means includes an agent computer with source data generating means for generating a source display of visual source data, and reformatting means for capturing designated portions of said source display and for converting the captured portions into a target display of said agent visual data, which target display has different visual content and appearance than said source display.

49. The telecommunication system of claim 48, wherein said agent visual data generating means includes agent visual data display means connected to said agent computer for displaying said source display in a visually perceptible manner, and wherein said agent computer includes a data interface port connected to said agent transfer means, an interface circuit for feeding said agent visual data to said data interface port and to said agent transfer means, and agent send actuating means for actuating said reformatting means to capture said designated portions of said source display and to convert them to said target display and for actuating said interface circuit to feed said target display as agent visual data to said agent transfer means.

50. The telecommunication system of claim 48, wherein said reformatting means is actuateable to copy data in designated portions of said source display and to insert said data into designated portions of said target display.

51. The telecommunication system of claim 48, wherein said reformatting means includes conditional criteria for comparing to data in said designated portions of said source display and screening means for prohibiting copying of data that does not meet said conditional criteria into said target display.

52. The telecommunication system of claim 48, wherein said reformatting means includes conditional criteria for comparing to data in said designated portions of said source display and to substitute character strings for insertion into said target display instead of said data in said designated portions of said source display that meet said conditional criteria.

53. The telecommunication system of claim 48, wherein said agent computer includes auxiliary agent data entry means for entering additional data into said target display that is not in said source display.

54. The telecommunication system of claim 53, wherein said auxiliary agent data entry means includes a keyboard connected to said agent computer.

55. The telecommunication system of claim 15, wherein said agent tone generator means produces an agent termination character at the end of each agent visual data.

56. The telecommunication system of claim 55, wherein said agent microcontroller means is programmed to select said low data transmitting and receiving rate when said agent visual data is shorter than a threshold data length and to select a data transmitting and receiving rate that is faster than said low data transmitting and receiving rate when said agent visual data is at least as long as said threshold data length.

57. The telecommunication system of claim 56, wherein said threshold data length is about four characters.

58. The telecommunication system of claim 56, wherein said agent microcontroller means is programmed to detect said agent termination character, to determine the length of said agent visual data preceding said agent termination character, to compare the length of said agent visual data to said threshold data length, and to actuate said agent modem means to produce said agent rate signal that is indicative of the selected data transmitting and receiving rate.

59. The telecommunication system of claim 58, wherein said agent rate signal comprises simultaneous tones having both said first and said second tone frequencies to indicate said high data transmitting and receiving rate.

60. The telecommunication system of claim 58, wherein said agent rate signal comprises a single tone having said first tone frequency to indicate said low data transmitting and receiving rate.

61. The telecommunication system of claim 58, wherein said agent rate signal comprises a single tone generated at said second tone frequency to indicate said medium data transmitting and receiving rate.

62. The telecommunication system of claim 55, wherein said subscriber microcontroller means is programmed to recognize said agent termination character as being indicative of the end of said agent visual data and to generate a subscriber acknowledgement signal in response to said agent termination character and to send said subscriber acknowledgement signal to said subscriber modem means for modulation and transmission on said POTS.

63. The telecommunication system of claim 62, wherein said subscriber microcontroller means is also programmed to generate a success report in response to said agent termination character for display on said subscriber visual data display means.

64. The telecommunication system of claim 62, wherein said subscriber microcontroller means is also programmed to recognize when said agent termination character is not at the end of said agent visual data received by said subscriber transfer means and to generate an error report for display on said subscriber visual data display means.

65. The telecommunication system of claim 62, wherein said subscriber microcontroller means is programmed to reconfigure said subscriber modem means in response to said agent termination character to generate and transmit on said POTS a subscriber rate signal that is indicative of said low rate, then to reconfigure said subscriber modem means again to transmit data at said low rate, and to produce said subscriber acknowledgement signal in data form to said subscriber modem means for transmission on said POTS.

66. The telecommunication system of claim 65, wherein said agent modem means is also for detecting subscriber ram signals on said POTS and for distinguishing characteristics of subscriber rate signals that are indicative respectively of said low, medium, and high data transmitting and receiving rates, and for signaling said agent microcontroller means in a manner that reflects said rate distinguishing characteristics of the subscriber rate signals detected.

67. The telecommunication system of claim 66, wherein said agent microcontroller means is programmed to recognize the rate distinguishing characteristics of the subscriber rate signals and to reconfigure said agent modem means to receive said acknowledgement signal data at the data transmitting and receiving rate indicated by said subscriber rate signal.

68. The telecommunication system of claim 66, wherein said agent microcontroller means is programmed with a maximum acknowledgement time limit and to measure time elapsed from said reconfiguring of said agent modem means for detecting said subscriber rate signal, and wherein said microcontroller means is also programmed to initiate a retry procedure when said time elapsed exceeds said maximum acknowledgement time limit by resending said agent start tone, said agent flag signals, and said agent visual data in sequence to said subscriber station and then to reconfigure again said agent modem means for detecting said subscriber rate signal.

69. The telecommunication system of claim 68, wherein said agent microcontroller means is programmed to reconfigure said agent modem means to transmit said agent visual data at a first retry rate at least as high as the rate at which said agent visual data was transmitted initially for a predetermined number of said retry procedures.

70. The telecommunication system of claim 69, wherein said agent microcontroller means is programmed to reconfigure said agent modem means to transmit said agent visual data a predetermined number of times at a second retry rate lower than said first retry rate if none of said retries at said first retry rate result in receipt of said subscriber rate signal by said agent modem means, and to reconfigure said agent modem means after each such retry at said second retry rate for detecting said subscriber rate signal and to terminate said retry procedure whenever said subscriber rate signal is detected by said agent modem means.

71. The telecommunication system of claim 70, wherein said agent microcontroller means is programmed to terminate said retry procedure when said agent visual data has been transmitted at said second retry rate a preset number of times without detecting said subscriber rate signal.

72. The telecommunication system of claim 55, wherein said subscriber station includes subscriber visual data generating means connected to said subscriber microcontroller means for generating subscriber visual data, said subscriber visual data being programmed to produce an agent termination character at the end of each subscriber visual data.

73. The telecommunication system of claim 72, wherein said agent termination character and said subscriber termination character is any one of the characters ETX, ETB, EOT, wherein said ETX character signals that an open-ended exchange of data is allowed between said agent station and said subscriber station, said ETB character signals that one data response is allowed from said subscriber station, and said EOT character indicates that no data response from said subscriber station is allowed.

74. The telecommunication system of claim 73, wherein said agent microcontroller means is programmed to detect and distinguish whether said agent termination character is an ETX, ETB, or EOT, character.

75. The telecommunication system of claim 74, wherein said agent microcontroller means is programmed to reconfigure said agent modem means to detect a subscriber rate signal on said POTS in response to an ETX character after said agent visual data is transmitted and then to reconfigure said agent modem means in response to said subscriber rate signal to receive subscriber visual data from said subscriber station on said POTS at the rate indicated by said subscriber rate signal.

76. The telecommunication system of claim 75, wherein said agent microcontroller means is programmed to determine whether said subscriber termination character at the end of said subscriber visual data is an ETX character, and, if it is an ETX character, then to leave said agent modem means configured to transmit data.

77. The telecommunication system of claim 76, wherein said agent microcontroller means is programmed to determine whether said subscriber termination character at the end of said subscriber visual data is an ETB character, if it is not an ETX character, and if it is an ETB character, then to leave said agent modem means configured to transmit data.

78. The telecommunication system of claim 77 wherein said agent microcontroller means is programmed to determine whether an EOT character is present at the end of said subscriber visual data, if an ETB character is not detected, and, if not, to terminate data transfer and reception by said agent station.

79. The telecommunication system of claim 78, wherein said agent microcontroller means is programmed to terminate data transfer and reception by said agent station if an EOT character is detected at the end of said subscriber visual data.

80. The telecommunication system of claim 79, said agent visual data generator means is programmed to produce one additional agent visual data after said ETB character at the end of said subscriber visual data is detected, and wherein said agent microcontroller means is programmed to cause said agent modem means to transmit said additional agent visual data on said POTS and then to terminate said data transfer and reception by said agent station, while said subscriber microcontroller means is programmed to reconfigure said subscriber modem means to receive said additional agent visual data and transfer it to said subscriber visual display means and then to convert the subscriber station to a subscriber voice mode.

81. The telecommunication system of claim 80, wherein said agent microcontroller means is programmed to reconfigure said agent modem to receive data in response to detection of said ETB character at the end of said agent visual data, said subscriber microcontroller means is programmed to reconfigure said subscriber modem means to transmit one additional subscriber visual data and then to convert the subscriber station to a subscriber voice mode, and said agent microcontroller means is programmed to terminate data transfer and reception by said agent station after reception of said additional subscriber visual data.

82. The telecommunication system of claim 81, wherein said agent microcontroller means is programmed to terminate data transfer and reception by said agent station when said EOT character is not detected at the end of said agent visual data.

83. The telecommunication system of claim 82, wherein said agent microcontroller means is programmed to terminate data transfer and reception by said agent station when said EOT character is detected at the end of said agent visual data.