thereafter the sender terminal waits for the sender 39 s command step s 270 if no further receivers are intended to receive the text message the sender terminal terminates the text message transmission process and returns to the idle mode step s 290 however if further receivers exist to which the text message is to be transmitted the sender terminal receives the input of phone numbers of the corresponding receivers step s 280 at this time the receiver phone number input process is the same as the receiver phone number input of step s 200 if the phone numbers of the new receivers are inputted a message e g u201c retransmission u201d appears on the display section of the sender terminal and the sender terminal waits for the sender 39 s command of text message transmission not illustrated when the command is received the sender terminal repeats the above steps s 240 s 250 and s 270 if any further receivers to which the text message is to be transmitted exist after the completion of the collective transmission to the plurality of receivers the sender terminal performs the text message transmission steps s 280 s 240 s 250 and s 270 successively also the phone numbers.