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US 4,905,272 AGranted
PABX cordless telephone system
AssigneeU.S. Philips Corporation
InventorsPetrus P. Van de Mortel, Johannes C. F. Van Loon
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AssigneeU.S. Philips Corporation
InventorsPetrus P. Van de Mortel, Johannes C. F. Van Loon
Estimating the term…
A PABX cordless telephone system comprising a base station (10) and a plurality of handset (HS1 to HS5). The base station is connected to the public switching network and communicates with each handset by way of a respective duplex radio link. The operation of the PABX system is controlled by a micro-controller (16) in the base station. Micro-controllers are also present in each of the handsets. Security in the radio communication via the duplex radio links is provided by assigning an n-bit security address code, where n for example comprises 16 bits, to each handset. The signalling protocols in setting-up calls require the transmission of the full n-bit security code. In the interim periods the base station (10) carries out a security check on the handsets forming its system. Time, memory capacity in the micro-controllers and battery current can be saved while simultaneously achieving a high degree of security if the security check is carried out using m bits of the security codes where m<n and m is typically equal to 8.
A PABX cordless telephone system comprising a base station and a plurality of disconnectable handsets, the base station and the handsets each having a respective transceiver for communication to and from each other by way of a respective duplex radio link, the base station having a micro-controller for controlling the system, and each handset having a respective micro-controller for controlling various functions in the handset, each respective micro-controller in the handsets including a respective memory for storing a respective n-bit security address code which is used in call set-up protocol with the base station and the micro-controller in the base station including a memory for storing all the respective security address codes, wherein the micro-controller in the base station is programmed to carry out security checks on the handsets by using m bits of the respective security address codes where m<n.
A method of operating a PABX cordless telephone system comprising a base station and a plurality of handsets, each handset having an n-bit security address code which is also stored in the base station, wherein during call set-up protocols the full n-bit security codes are used in duplex radio links between the base station and the handsets and wherein the base station makes security checks on the handsets using m bits of the n-bit security code address, where m<n.
A method for operating a PABX cordless telephone system which includes a base station and a plurality of disconnectable handsets, each respective handset having a respective n-bit security address code which is stored in both the base station and in the respective handset, comprising the steps of:
Dependencies are inferred from the claim text.