Data transmission/reception apparatus

A data reception apparatus comprising:

• means for receiving data according to full duplex communication;
• means for receiving data according to half duplex communication;
• means for receiving a test signal prior to data reception;
• means for transmitting a predetermined response signal responsive to the test signal during reception of the test signal;
• and
• means for discriminating whether the data is received or not within a predetermined period of time after the response signal is transmitted, said discriminating means selecting one of said full duplex communication and said half duplex communication on the basis of the discrimination result.

A data transmission apparatus comprising:

• means for transmitting data by full duplex communication;
• means for transmitting a test signal of the data communication prior to the data transmission;
• and
• means for detecting whether a full duplex communication backward signal is received from a receiver during transmission of the test signal by said test signal transmitting means and for determining whether full duplex communication is possible on the basis of a detection result, said backward signal being a response signal to the test signal.

A data transmission apparatus comprising:

• a memory for storing data;
• means for performing data transmission by full duplex communication;
• means for performing a test of data communication prior to the data transmission;
• and
• means for detecting whether a full duplex communication backward signal is detected from a receiver during a test period and for determining whether full duplex communication is possible on the basis of a detection result,
• wherein the test period of said testing means is set in accordance with a capacity of said memory, and said determining means determines that full duplex communication is impossible when the backward signal is not received during the test period.