A sender telephone receives a text message to send to a receiver telephone. The sender telephone determines the transmission delay time by sending a predetermined message to receiver telephone, based on the time it receives an address complete message and a release message. The sender telephone determines a constant value that is greater than the transmission delay time and in response to the determining the constant value, ringing the receiver telephone to transmit the received inputted text message. A receiver telephone receives a predetermined message from a caller telephone to determine a transmission delay time, based on the time it receives the address complete message and a release message. The receiver telephone determines a constant value that is greater than the transmission delay time. The receiver telephone receives incoming rings from the caller telephone and converts the received rings into a text message to be displayed.