A data communication apparatus includes a communication section that performs a pre-communication protocol with a destination terminal and transmits data to a destination terminal. A memory stores data and communication parameters corresponding to each destination terminal, the communication parameters being utilized to perform communication with the destination terminal. When destination terminal data is stored in the memory, a controller reads the communication parameters corresponding to the destination terminal from the memory, performs the pre-communication protocol with the destination terminal, using the read communication parameters, and omits at least a communication protocol for line probing. When destination terminal data is not stored in said memory, the controller performs the pre-communication protocol with the destination terminal, using communication parameters acquired from the destination terminal under the pre-communication protocol without omitting the communication protocol for line probing.