METHOD AND APPARATUS FOR TRANSMITTING MESSAGES IN A TELECOMMUNICATION SYSTEM

A method and an apparatus for implementing the method, which allow a transmitter (100) of a digital telecommunication system transmitting speech to transmit predetermined messages to a receiver (102) over a speech channel (108). Messages (114) are transmitted from the transmitter (100) to the receiver (102) on the speech channel (108) in such a way that they are encoded in some of the speech coding bits, whereby the speech coding bits selected for message transmission have been selected in such a way that they affect the quality of speech as little as possible. Most preferably, the speech coding bits used for transmitting messages are protected by channel coding (702, 704). Speech coding bits are "stolen" for message transmission only for very short periods at a time and only for exactly the time it takes to transmit the messages (114); at other times, the entire speech channel (108) is used normally for speech transmission.