Telephone terminal and method for telephone calls between a calling terminal and a called terminal for optimizing the communication charge

摘要

The two mode transmission system has a terminal (5) which examines the state of a receive terminal (2) from the two possible states. The mechanism also determines whether communications in real time, or communications at a delayed time, is required. There is also a mechanism for constructing and temporarily storing a message locally, for transmitting to the called terminal via a second communication network operating in off line time, while the terminal is operating in an off line mode. The terminal may also include a mechanism for transmitting a signal indicating an operating condition, to the calling terminal, in response to the detection of a call.