TELECOMMUNICATION SYSTEM WITH RADIO LINK

摘要

A mobile subscriber station served by a telephone network is coupled by a radio link with an individually associated stationary relay station directly connected to that network. The two stations are able to communicat with each other, over a radius of about 50 meters, on any of 40 channels available to all the posts of subscriber and relay stations in the neighborhood. Each station of a post includes a transmitter and a receiver operating at about 900 MHz; in the idle state of the post, the receivers of both stations continuously scan the available channels to determine their free or busy condition. A person wishing to make an outgoing call causes the transmitter of the subscriber station to send out a predetermined code word which is picked up by the receiver of the associated relay station in its scanning operation and, upon verification by a code comparator; initiates the emission of a handshake signal to the subscriber station wre reupon the channel is seized to let the call proceed over the network. Similarly, the arrival of an incoming call at the relay station results in the transmission of the same or another predetermined code word to the subscriber station on a free channel which is seized for reception of the call after the code has been verified. With the code or codes used for outgoing and incoming calls uniquely assigned to a particular team. privacy is assured.