Data communication system

Claim 2

A data communication system comprising: data receiving means for receiving data; data memory means for storing data received by said data receiving means; recording means for recording the data stored in said data memory means; acknowledgement signal generating means for transmitting an acknowledgement signal representative of safe receipt of one page of data when data of one page has been correctly received; information memory means for storing information representative of a recording condition of the data stored in said data memory means; and information output means for producing information indicative of the fact that there are non-recorded data in accordance with the information of said information memory means, wherein, in the case of power failure in recording data by said recording means, said information output means outputs information indicative of the existence of non-recorded data in accordance with the information of said information memory means.

Claim 3

A data communication system according to claim 1, further comprising retransmission demand signal generating means for checking the received data for any error and, when an error exists in the received data, transmitting a retransmission demand signal demanding retransmission of the data including the error.

Claim 4

A data communication system according to claim 2, wherein said acknowledgment signal generating means transmits said acknowledgment signal when no error exists in the received data of one page.

Claim 5

A data communication system according to claim 3, wherein said data memory means holds the received page data until all the data for the new page are correctly received.

Claim 6

A data communication system according to claim 4, wherein said received data of one page is the data of an imaginary page of a predetermined volume.

Claim 7

A data communication system comprising: data receiving means for receiving data; data memory means for storing data received by said data receiving means; recording means for recording data stored in said data memory means; acknowledgement signal generating means for transmitting an acknowledgement signal representative of safe receipt of one page of data when data of one page has been correctly received; information memory means for storing information representative of a recording condition of the data stored in said data memory means; and information output means for producing information indicative of the fact that there are non-recorded data in accordance with the information of said information memory means, wherein, in the case of power failure in recording data by said recording means, said information output means outputs information indicative of the existence of non-recorded data in accordance with a power-on after the power failure.

Claim 8

A data communication system comprising: data receiving means for receiving data; data memory means for storing data received by said data receiving means; recording means for recording data stored in said data memory means; acknowledgement signal generating means for transmitting an acknowledgement signal representative of safe receipt of one page of data when data of one page has been correctly received; information memory means for storing information representative of a recording condition of the data stored in said data memory means; and information output means for producing information indicative of the fact that there are non-recorded data in accordance with the information of said information memory means, wherein, in the case of power failure in recording data by said recording means, said information output means outputs information indicative of the existence of non-recorded data in accordance with a power-on after the power failure.

Claim 9

A data communication system comprising: first means for receiving signals of a high transmission speed; and second receiving means for receiving signals of a low transmission speed; control means for switching said first and second receiving means to enable a selected one of said receiving means to receive signals; wherein said control means determines whether a predetermined one of said high-speed signals has been detected continuously throughout a predetermined period and for effecting switching to said first receiving means when said predetermined high-speed signal has been detected continuously throughout said predetermined period, and, when said predetermined high-speed signal has not been detected continuously throughout said period, said control means enables said second receiving means to receive said low-speed signals for a time corresponding to a time required for the transmission of a predetermined unit of said high-speed signals.

Claim 10

A data communication system comprising: first means for receiving signals of a high transmission speed; and second receiving means for receiving signals of a low transmission speed; control means for switching said first and second receiving means to enable a selected one of said receiving means to receive signals; wherein said control means determines whether a predetermined one of said high-speed signals has been detected continuously throughout a predetermined period and for effecting switching to said first receiving means when said predetermined high-speed signal has been detected continuously throughout said predetermined period, and, when said predetermined high-speed signal has not been detected continuously throughout said period, said control means enables said second receiving means to receive said low-speed signals for a time corresponding to a time required for the transmission of a predetermined unit of said high-speed signals.

Claim 11

A data communication system according to claim 7, wherein said control means judges whether a high-speed flag has been detected continuously throughout said predetermined period.

Claim 12

A data communication system according to claim 8, wherein if said high-speed flag has been detected continuously throughout said predetermined period, the control means enables said first means to receive signals of the high transmission speed and if said high-speed flag has not been detected continuously throughout said predetermined period, the control means switches to said second means for receiving signals of the low transmission speed.

Claim 13

A data communication system according to claim 7, wherein said first receiving means is capable of receiving high-speed signals of different transmission speeds.

Claim 14

A data communication system according to claim 7, further comprising transmission means for transmitting a low-speed signal.

Claim 15

A data communication system according to claim 7, wherein said high-speed signals include image signals, and said low-speed signals include a control signal.

Claim 16

A data communication system according to claim 12, further comprising: transmission means for transmitting said control signal; and error detection means capable of detecting error in the received image signals, wherein, when an error exists in the received image signals, said control means enables said transmission means to transmit a signal demanding retransmission of the image signals in which said error has occurred.

Claim 17

A data communication system comprising: first means for receiving signals of a high transmission speed; second receiving means for receiving signals of a low transmission speed; and control means for switching said first and second receiving means to enable a selected one of said receiving means to receive signals, wherein said control means determines whether a predetermined one of said high-speed signals has been detected continuously throughout a predetermined period and for effecting switching to said first receiving means when said predetermined high-speed signal has been detected continuously throughout said predetermined period, and, when said predetermined high-speed signal has not been detected continuously throughout said period, said control means enables said second receiving means to receive said low-speed signals for a time corresponding to a time required for the transmission of a predetermined unit of said high-speed signals, wherein said high-speed signals include image signals, and said low-speed signals include a control signal, and wherein said control means executes an error routine so as to open a communication circuit both when no frame of image signals is detected in a period which is the sum of an image transmission time corresponding to the current transmission speed and a margin time, and when no effective frame of image signals is detected in a predetermined time from the detection of a previous effective frame of image signals.

Claim 18

A data communication system comprising: first means for receiving signals of a high transmission speed; second receiving means for receiving signals of a low transmission speed; and control means for switching said first and second receiving means to enable a selected one of said receiving means to receive signals, wherein said control means determines whether a predetermined one of said high-speed signals has been detected continuously throughout a predetermined period and for effecting switching to said first receiving means when said predetermined high-speed signal has been detected continuously throughout said predetermined period, and, when said predetermined high-speed signal has not been detected continuously throughout said period, said control means enables said second receiving means to receive said low-speed signals for a time corresponding to a time required for the transmission of a predetermined unit of said high-speed signals, wherein said high-speed signals include image signals, and said low-speed signals include a control signal, and wherein said control means executes an error routine so as to open a communication circuit both when no frame of image signals is detected in a period which is the sum of an image transmission time corresponding to the current transmission speed and a margin time, and when no effective frame of image signals is detected in a predetermined time from the detection of a previous effective frame of image signals.

Claim 19

A data communication system comprising: receiving means for receiving data; detection means for detecting whether an uncorrectable error frame of data exists in the received data; recording means for recording the received data; and control means responsive to the detection for enabling said recording means to record, when the presence of error has been detected by said detecting means, a message indicative of the presence of the error together with the recorded received data, wherein the recording of the message indicative of the presence of the error is conducted on the basis of a physical page of a sending side, wherein said data received is image data, and wherein the received image data is image data of a long continuous original page of the sending side, and said recording means records the received image data on a plurality of cut sheets of a predetermined size, said message indicative of the presence of error being recorded on each of a plurality of cut sheets corresponding to one long continuous original of the sending side.

Claim 20

A data communication system comprising: receiving means for receiving data; detection means for detecting whether an uncorrectable error frame of data exists in the received data; recording means for recording the received data; and control means responsive to the detection for enabling said recording means to record, when the presence of error has been detected by said detecting means, a message indicative of the presence of the error together with the recorded received data, wherein the recording of the message indicative of the presence of the error is conducted on the basis of a physical page of a sending side, wherein said data received is image data, and wherein the received image data is image data of a long continuous original page of the sending side, and said recording means records the received image data on a plurality of cut sheets of a predetermined size, said message indicative of the presence of error being recorded on each of a plurality of cut sheets corresponding to one long continuous original of the sending side.