EP0304998A2
Expired / Lapsed
EP
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PABX cordless telephone system
Assignee: Koninklijke Philips NV
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Filing: 1988-08-18
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Granted: —
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Expires: 2008-08-18
Abstract
Abstract 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 whilst 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 is typically equal to 8.
Inventors
- 👤 Petrus Paulus Van De Mortel
- 👤 Johannes Cornelus Fransiscus Van Loon
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 19:12
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/72; H04M1/725; H04M1/727; H04M1/72502; H04M1/72505
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
138 words
A PABX cordless telephone system comprising a base station and a plurality of handsets, the base station and the handsets each having a 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 micro-controller for controlling various functions is the handset, the micro-controller in the handset including a memory in which is stored an 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 assigned security address codes, wherein the micro-controller in the base station is programmed to carry-out security checks on its associated handsets by using m-bits of the n-bit security address code where m < n.
Claim 2
Dependent Claim
138 words
A PABX cordless telephone system comprising a base station and a plurality of handsets, the base station and the handsets each having a 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 micro-controller for controlling various functions is the handset, the micro-controller in the handset including a memory in which is stored an 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 assigned security address codes, wherein the micro-controller in the base station is programmed to carry-out security checks on its associated handsets by using m-bits of the n-bit security address code where m < n.
Claim 3
Dependent Claim
23 words
A system as claimed in claim 1, wherein the security check is made using the m-least significant bits of each security address code.
Claim 4
Dependent Claim
13 words
A system as claimed in claim 1 or 2, wherein n=16 and m=8.
Claim 5
Dependent Claim
148 words
A system as claimed in claim 1, 2 or 3, wherein each handset has a rechargeable battery, the base station has means for recharging in situ the battery in each handset, the micro-controller includes a pseudo-random counter which is electrically coupled via the battery charger contacts and the battery to the micro-controller in the handset so that the security address code of the handset is changed during the battery charging operation, the micro-controller in the handset causes its transceiver to transmit the new security address code via the duplex radio link to the base station, the micro-controller has means to compare the received security code with that relayed to the handset via the battery charger contacts and if they are equal it instructs the old code stored in the memories of the micro-controllers of the base station and the relevant handset to be overwritten by the new code.
Claim 6
Independent Claim
30 words
A system as claimed in any one of claims 1 to 4, wherein the security check by the base station micro-controller is effected by scanning its associated handsets in sequence.
Claim 7
Dependent Claim
24 words
A PABX cordless telephone system constructed and arranged to operate substantially as hereinbefore described with reference to and as shown in th eaccompanying drawings.
Claim 8
Dependent Claim
24 words
A PABX cordless telephone system constructed and arranged to operate substantially as hereinbefore described with reference to and as shown in th eaccompanying drawings.
Claim 9
Independent Claim
81 words
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.
Claim 10
Independent Claim
81 words
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.
Claim 11
Dependent Claim
19 words
A method as claimed in claim 7, wherein the duplex radio links are scanned sequentially by the base station.
Claim 12
Dependent Claim
33 words
A method as claimed in claim 7 or 8, wherein the signalling associated with the security check is carried out in a part of the channel frequency band above that used for speech.
Claim 13
Independent Claim
24 words
A method as claimed in any one of claims 7 to 9, wherein the m least6significant bits of the security address code are used.
Claim 14
Independent Claim
20 words
A method as claimed in any one of claims 7 to 10, wherein n = 16 and m = 8.
Claim 15
Independent Claim
13 words
A method of operating a PABX cordless telephone system substantially as hereinbefore described.
Claim 16
Independent Claim
13 words
A method of operating a PABX cordless telephone system substantially as hereinbefore described.
References Cited (Backward Citations)
No citation records indexed.
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