U.S. Philips Corporation

Georg Ranner

Jurgen Hoflinger

Manfred Tasto

Manfred Sondermann

Christian Behr

Erwin Kosmann

Rainer Blasius

In cordless telephone sets comprising at least one base station and at least one handset, an exchange of identification codes takes place between the base station and the handset. In order to realise greater flexibility with cordless telephone sets, the invention proposes to establish a connection between the handset and the base station also by means of a second identification code stored in the base station. In this manner, any user without knowing the identification codes to be exchanged between the handset and the base station can sign on and sign off a handset at any compatible base station, provided that he knows the second identification code.

Cordless telephone set with secure communication protocol

With cordless telephones it is a known fact that each pair of radio stations has m radio channels out of n possible radio channels in common. During a test cycle the mobile unit examines only the common radio channels. Consequently, the test period required for testing only the common channels is shorter than the time necessary for testing all channels. If, by chance, all common channels are busy or if such a situation is the result of a malfunctioning, establishing a link between the base unit and the mobile unit is no longer possible. In the proposed embodiment of a cordless telephone, reliably establishing a link is guaranteed in that in a first test phase the common channels and in a second test phase all n radio channels are tested. A field of application of the invention is the cordless telephone.

Identification code search in a communication device

For synchronizing a data block in a receiver, there are transmitted consecutively and prior to the data block: a first bit sequence of alternating '0' and '1' levels for determining the bit clock and a second bit sequence for determining the block synchronization by correlation. In known methods of determining the bit clock, the phase range of the individual bits of the received digital signal is divided into sub-intervals and the phase position of the bit clock is determined on account of the number of edges in these sub-intervals. In order to avoid fading and phase jitter having a detrimental effect on the bit synchronism, more specifically when transmitting through radio transmission links, N-phase-shifted clocks having the same clock frequency are generated in the receiver by means of which the first bit sequence is sampled. The clock for which the number of sample-value changes of the first bit sequence is established as having a predeterminable minimum value during a predeterminable time-interval is utilized as the phase synchronous bit clock.

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Lauf, Germany

Georg Ranner