Data communication apparatus and facsimile apparatus

A facsimile apparatus comprising:

• a modem that is able to perform communication in a full duplex mode, said modem performing communication in units of data blocks;
• and
• a protocol signal generation circuit that includes a synchronization signal generation circuit,
• wherein, in a case where a same protocol signal as that generated by said protocol signal generation circuit and sent previously is possibly resent, a synchronization signal from the synchronization signal generation circuit is sent following the protocol signal to maintain the communication in the full duplex mode, the protocol signal comprising a signal other than a data block;
• and
• wherein the synchronization signal is continuously sent after the protocol signal is sent until an acknowledgment signal is received.

A facsimile apparatus comprising:

• a modem that is able to perform communication in a full duplex mode;
• a protocol signal generation circuit that includes a synchronization signal generation circuit;
• and
• a high rate signal generation circuit adapted to transmit an image signal of a rate different from a rate of a protocol signal,
• wherein a synchronization signal is sent from the synchronization signal generation circuit following sending of a high rate signal by said high rate signal generation circuit to maintain the communication in the full duplex mode, and
• wherein a rate of the synchronization signal is equal to the rate of the protocol signal and is different from the rate of the image signal.

A facsimile apparatus comprising:

• a modem that is able to perform communication in a full duplex mode;
• a protocol signal generation circuit that includes a synchronization signal generation circuit;
• and
• a high rate signal generation circuit adapted to transmit an image signal of a rate different from a rate of a protocol signal,
• wherein a synchronization signal is continuously sent from the synchronization signal generation circuit following sending of a high rate signal by said high rate signal generation circuit to maintain the communication in the full duplex mode, until an acknowledge signal of a predetermined protocol signal is received, and, when the acknowledge signal is received, the sending of the synchronization signal is stopped, and
• wherein a rate of the synchronization signal is equal to the rate of the protocol signal and is different from the rate of the image signal.

A facsimile apparatus comprising:

• a modem that is able to perform communication in a full duplex mode;
• a protocol signal generation circuit that includes a synchronization signal generation circuit;
• and
• a high rate signal generation circuit adapted to transmit an image signal of a rate different from a rate of a protocol signal,
• wherein a synchronization signal is sent after a start of sending of the protocol signal except during the sending of the protocol signal and except during reception of a high rate signal to maintain the communication in the full duplex mode, and
• wherein a rate of the synchronization signal is equal to the rate of the protocol signal and is different from the rate of the image signal.

A communication apparatus comprising:

• a modem that is able to perform communication in a full duplex mode, said modem performing communication in units of data blocks;
• and
• a protocol signal generation circuit that includes a synchronization signal generation circuit,
• wherein a synchronization signal from the synchronization signal generation circuit is sent between protocol signals generated by said protocol signal generation circuit to maintain the communication in the full duplex mode, a protocol signal comprising a signal other than a data block;
• and
• wherein the synchronization signal is continuously sent after a protocol signal is sent until an acknowledgment signal is received.

A communication apparatus comprising:

• a modem that is able to perform communication in a full duplex mode, said modem performing communication in units of data blocks;
• and
• a protocol signal generation circuit that includes a synchronization signal generation circuit,
• wherein, in a case where a same protocol signal as that generated by said protocol signal generation circuit and sent previously is possibly resent, a synchronization signal from the synchronization signal generation circuit is sent following the protocol signal to maintain the communication in the full duplex mode, the protocol signal comprising a signal other than a data block;
• and
• wherein the synchronization signal is continuously sent after the protocol signal is sent until an acknowledgment signal is received.

A communication apparatus comprising:

• a modem that is able to perform communication in a full duplex mode;
• a protocol signal generation circuit that includes a synchronization signal generation circuit;
• and
• a high rate signal generation circuit adapted to transmit an image signal of a rate different from a rate of a protocol signal,
• wherein a synchronization signal is sent from the synchronization signal generation circuit following sending of a high rate signal by said high rate signal generation circuit, to maintain the communication in the full duplex mode, and
• wherein a rate of the synchronization signal is equal to the rate of the protocol signal and is different from the rate of the image signal.

A communication apparatus comprising:

• a modem that is able to perform communication in a full duplex mode;
• a protocol signal generation circuit that includes a synchronization signal generation circuit;
• and
• a high rate signal generation circuit adapted to transmit an image signal of a rate different from a rate of a protocol signal,
• wherein a synchronization signal is continuously sent from the synchronization signal generation circuit following sending of a high rate signal of said high rate signal generation circuit to maintain the communication in the full duplex mode, until an acknowledge signal by a predetermined protocol signal is received, and, when the acknowledge signal is received, the sending of the synchronization signal is stopped, and
• wherein a rate of the synchronization signal is equal to the rate of the protocol signal and is different from the rate of the image signal.

A communication apparatus comprising:

• a modem that is able to perform communication in a full duplex mode;
• a protocol signal generation circuit that includes a synchronization signal generation circuit;
• and
• a high rate signal generation circuit adapted to transmit an image signal of a rate different from a rate of a protocol signal,
• wherein a synchronization signal is sent after a start of sending of the protocol signal except during the sending of the protocol signal and except during reception of a high rate signal to maintain the communication in the full duplex mode, and
• wherein a rate of the synchronization signal is equal to the rate of the protocol signal and is different from the rate of the image signal.

A data communication apparatus for communicating in a full duplex communication mode, said apparatus comprising:

• a sending circuit adapted to send a first signal for allowing the full duplex communication mode;
• a protocol signal communication circuit adapted to perform protocol signal communication in the full duplex communication mode after sending of the first signal and without causing a signal interruption longer than a predetermined time interval, to maintain the communication in the full duplex communication mode;
• a data communication circuit adapted to perform data communication in a half duplex communication mode after termination of the protocol signal communication;
• a transmission/reception replacement circuit adapted to switch transmission/reception of data with a destination station following termination of the data communication, in order to continue the data communication;
• and
• a control circuit adapted to cause said sending circuit to send the first signal in a transmission/reception replacement operation by said transmission/reception replacement circuit without disconnection of a line, said control circuit causing said protocol signal communication circuit to perform the protocol signal communication in the full duplex communication mode, and causing said data communication circuit to conduct the data communication in the half duplex communication mode,
• wherein the first signal sent by said sending circuit disables an echo suppressor of a communication network used by said data communication apparatus.

A data communication apparatus for communicating in a full duplex communication mode, said apparatus comprising:

• a sending circuit adapted to send a first signal for allowing the full duplex communication mode,
• wherein the first signal sent by said sending circuit disables an echo suppressor of a communication network used by said data communication apparatus;
• a protocol signal communication circuit adapted to perform protocol communication in the full duplex communication mode after sending of the first signal and without causing a signal interruption longer than a predetermined time interval, to maintain the communication in the full duplex communication mode;
• a data communication circuit adapted to perform data communication in a half duplex communication mode after termination of the protocol signal communication;
• a transmission/reception replacement circuit adapted to switch transmission/reception of data with a destination station following termination of the data communication, in order to continue the data communication;
• a flag signal communication circuit adapted to communicate a flag signal following a post-protocol signal after transmission of data in a transmission/reception replacement operation to prevent a signal interruption longer than the predetermined time interval from occurring and without disconnection of a line;
• and
• a control circuit adapted to cause said protocol signal communication circuit to communicate a protocol signal of the transmission/reception replacement operation without causing a signal interruption longer than the predetermined time interval, to continue the protocol signal communication in the full duplex communication mode, and to cause said data communication circuit to perform the data communication in the half duplex communication mode.

A data communication method for performing communication in a full duplex communication mode, said method comprising the steps of:

• sending a first signal to allow a full duplex communication mode;
• performing protocol signal communication in the full duplex communication mode after said sending of the first signal and without causing a signal interruption longer than a predetermined time interval, to maintain the communication in the full duplex communication mode;
• performing data communication in a half duplex mode after termination of the protocol signal communication;
• switching transmission/reception of data with a destination station following termination of the data communication, in order to continue the data communication;
• and
• sending a signal of a transmission/reception replacement operation without disconnection of a line, performing the protocol signal communication in the full duplex communication mode, and performing the data communication in the half duplex communication mode,
• wherein the first signal disables an echo suppressor of a communication network used for the communication.

A data communication method for performing communication in a full duplex communication mode, said method comprising the steps of:

• sending a first signal to allow a full duplex communication mode,
• wherein the first signal disables an echo suppressor of a communication network used in said data communication method;
• performing protocol signal communication in the full duplex communication mode after said sending of the first signal and without causing a signal interruption longer than a predetermined time interval, to maintain the communication in the full duplex communication mode;
• performing data communication in a half duplex mode after termination of the protocol signal communication;
• switching transmission/reception of data with a destination station following termination of the data communication, in order to continue the data communication;
• communicating a flag signal following a post-protocol signal after transmission of data of a transmission/reception replacement operation to prevent a signal interruption longer than the predetermined time interval from occurring and without disconnection of a line;
• and
• communicating a protocol signal of the transmission/reception replacement operation, without causing a signal interruption longer than a predetermined time interval, continuing the protocol signal communication in the full duplex communication mode, and performing the data communication at a half duplex communication mode.