1. A portable terminal apparatus comprising: a first communication unit which connects to a server on a network and performs data transmission; a second communication unit which connects to a communication apparatus and performs data transmission; a temporary storage unit which, using said first communication unit and said second communication unit at the time of relaying a. communication of data between said server and said communication apparatus, temporarily stores said data; and a control unit which controls said data communication of said first communication unit and said second communication unit asynchronously and in parallel at the time of relaying the communication of data between said server and said communication apparatus.