U.S. Philips Corporation

Sabine V Giorgi

Antoine Chouly

Bruno Ballarin

Petrus A Van Grinsven

Philippe Decotignie

Carel J Van Driel

Guillene E Teboul

Nicos Achilleoudis

A telephone includes circuits that enable a user of the telephone to receive incoming calls and set up outgoing calls. A controller puts the telephone interface in a blocking state to prevent normal use of the telephone when the interface receives a block signal, and puts the interface in a service state to make the telephone accessible. The telephone has a timing circuit that supplies the block signal to the controller after a given period of inactivity of the telephone to place the telephone in the blocking state. An erroneous unblocking code used a predetermined number of times puts the telephone in a state of total block which includes a power cut of the telephone. Turning on the telephone allows leaving the total block state.

Method for avoiding fraudulent use of a mobile radiotelephone by blocking an interface after a certain inactive period of time and mobile radiotelephone performing the same

In a transmission system for transmitting synchronous data portions and asynchronous data portions, a transmission frame includes regularly spaced synchronous data portions interleaved with asynchronous data portions. To insure that the packing density of asynchronous data portions is optimal, the position of the synchronous data portions is allowed to deviate from its nominal value to increase the packing rate of the asynchronous data portions.

Transmission system for synchronous and asynchronous data portions

A digital transmission system includes a receiver which is synchronized with a transmitter wherein a correlation is established between a reference sequence and an initialization sequence transmitted by the transmitter. The system further includes an equalizer for operating with a first part of the initialization sequence, and a correlator for operating with a second part of the initialization sequence. This makes it possible to enhance the established correlation with the reference frequency and realize the synchronization, with great precision.

Digital transmission system that can be synchronized with initialization

A communication system having a transmitter that supplies test sequences formed from several test frequencies and a receiver having test means for testing the quality of a channel. The test means calculates for the plurality of frequencies both the transfer function of the channel and the channel noise variance. By taking the noise caused by the receiver into account, the test means determine the most suitable frequency band and bit rate for the transmission. This information is supplied to the transmitter to establish the transmission.

Growing community of inventors

La Vareene St. Hilaire, France

Sabine V Giorgi