Abstract: A point to multipoint channel extension protocol and system are disclosed. More particularly, the system includes an extension protocol for extending a point to point radio link between a primary station and a secondary station to a point to multipoint radio link in which the primary station broadcasts to the secondary stations. This is done by first informing the handset to which a point to point radio link has been set up that an extension is to be done so that the handset can switch off its transmitter, and then transmitting extension messages to all handsets. Furthermore, a transfer and skipping protocols are proposed with a reliable connection establishment by using a double checking protocol for seizing a pair of free channels.

Abstract: A free channel double checking protocol and system are disclosed. More particularly, the system includes at least one primary radio station and a plurality of secondary radio stations, in which a secondary radio station is matched to a primary radio station and a wireless communication is established via a full duplex communication link. The primary and the secondary stations establish the communication link using a free channel double checking protocol. The free channel doubles checking protocol checks whether a free channel exists between stations. After setting up the communication link, a calling station may confirm to a called station that a reliable communication link has been established.

Abstract: In the microprocessor assembly of the base station (51) and of the mobile station of a wireless telephony device, a reduced-intercom mode is implanted intended for sound monitoring, which mode, once it is started from the base station (52), brings about the succession of the following events (53):reception in the mobile station by radio channel of the instruction to install in the reduced-intercom mode consisting of the inhibition of the ringing, the switching on of its microphone, the switching off of its loudspeaker and the automatic calling of the base station to cause the latter to switch on the loudspeaker and switch off the microphone, so as to establish an automatic calling of the mobile station from the base station (54).

Abstract: A communication system and method of connecting a mobile unit to a base station are disclosed where a connection code is stored in the base unit which is the serial number thereof. The connection code is either entered by the user of the mobile unit or is stored therein. This connection code is transmitted from the mobile unit to the base station before a communication between them is established. Such a communication is established if the connection code transmitted from the mobile unit equals to the connection code stored in the base unit.

Abstract: A channel is selected first, and immediately the received field is measured and digital Manchester code data are searched for. The digital signals are 100% Manchester code signals. After a predetermined first delay, the carrier level is tested and recorded in a memory. The smallest value among the various recorded values is selected; a fixed value is added thereto; and the value thus obtained is used as a threshold value for the level test. If the channel is free, another channel is selected. If the channel is occupied, one will wait for a second delay period, after which a test is performed to know whether data have been recognized. If nothing has been recognized, another channel is selected.