Abstract: A method of controlling the operation of a packet switched CDMA telecommunication network for controlling the operation of transmitters and receivers. The terminals of network users (U.sub.i,j) communicate with other terminals (U.sub.j,i) via a CDMA channel, and the terminal of each user is assigned a receiver code (r.sub.i,j) and a transmitter code (t.sub.i,j) used by the terminals for encoding packets to the other terminals of the network. To improve the performance of the network, the terminals sense the channel for the presence of the receiver codes (r.sub.i,j) and/or the transmitter codes (t.sub.i,j) at the different stages of the connection establishment, and the transmitting terminal (TER.sub.i) transmits encoded request packets (REQ) and data packets (DAT) to the channel on the basis of the sensing procedure, and the other communicating party, i.e. the receiving terminal (TER.sub.j), receives said encoded packets and transmits encoded acknowledgement packets (ACK) and busy tone packets to the channel.