EP0336079A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for controlling access to a communication system
Assignee: Motorola Solutions Inc
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Filing: 1989-02-16
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Granted: —
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Expires: 2009-02-16
Abstract
Abstract All subscribers operating within a communication system initially generate and transmit a random password and their ID code to the operation (control) center of a communication system. Thereafter, in a first embodiment, subscribers are commanded to modify (in a predetermined manner) and re-transmit their password and ID code either periodically or upon requesting access to the communication system. The modified password is retained as the current (authorized) password by both the subscriber and the system. In a second embodiment, subscribers are commanded to generate and transmit a new random password and their ID code to the system, which maintains a history of each subscriber's current and previous passwords. According to the invention, some of the subscribers having an unauthorized (duplicated) ID code may be inactive (off) when the subscriber is commanded to modify or generate a password. In this way, one of the subscribers having an unauthorized (duplicated) ID code will become out-of-sync with the system, and eventually transmit an unauthorized password. When the system receives an incorrect password for an out-of-sync subscriber, access to the communication system may be denied, and the subscribers that duplicate (or permit others to duplicate) ID codes may be identified.
Inventors
- 👤 Kenneth J. Zdunek
- 👤 Eric Reed Schorman
- 👤 Philip A. Bieri
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 20:25
CPC Classifications
H; H04; H04W; H04W12/00; H04W12/06; H04L; H04L63/00; H04L63/08; H04L63/083; H04W12/08; H04L63/10; H04L63/108
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
145 words
In a two-way communication system having a central unit and a plurality of subscriber units each having at least an identification code and a password code stored therein, a method of controlling access to the two-way communication system characterized by the steps of: in at least one of said plurality of subscriber units: (a) transmitting at least a call request code; (b) receiving a command code and modifying said password code in response thereto to provide a modified password code; (c) transmitting at least said modified password code and said identification code; at said central unit: (a) receiving at least said call request code; (b) transmitting said command code; (c) modifying said password code to provide an expected password code; (c) receiving at least said modified password code to provide a received password code; (d) comparing said expected password code to said received password code.
Claim 2
Dependent Claim
145 words
In a two-way communication system having a central unit and a plurality of subscriber units each having at least an identification code and a password code stored therein, a method of controlling access to the two-way communication system characterized by the steps of: in at least one of said plurality of subscriber units: (a) transmitting at least a call request code; (b) receiving a command code and modifying said password code in response thereto to provide a modified password code; (c) transmitting at least said modified password code and said identification code; at said central unit: (a) receiving at least said call request code; (b) transmitting said command code; (c) modifying said password code to provide an expected password code; (c) receiving at least said modified password code to provide a received password code; (d) comparing said expected password code to said received password code.
Claim 3
Dependent Claim
18 words
The method of claim 1, which includes the subscriber unit step of: (d) receiving a channel grant code;
Claim 4
Dependent Claim
30 words
The method of claim 1, which includes the central unit step of: (e) transmitting a channel grant code only if said expected password code correlates with said received password code.
Claim 5
Dependent Claim
27 words
The method of claim 1, which includes the central unit step of: (e) determining whether a subscriber unit is an authorized unit in response to step (d).
Claim 6
Dependent Claim
128 words
In a two-way communication system having a plurality of subscriber units each having at least an identification code and a first password code stored therein and at least one central unit designating said first password code as a current password code, a method of controlling access to the two-way communication system characterized by the steps of: in at least one of said plurality of subscriber units: (a) transmitting at least said call request code; (b) receiving a command code and generating a second password code in response thereto; (c) transmitting at least said second password code and said identification code; at said at least one central unit: (a) receiving at least said call request code; (b) transmitting said command code; (c) receiving at least said second password code.
Claim 7
Dependent Claim
128 words
In a two-way communication system having a plurality of subscriber units each having at least an identification code and a first password code stored therein and at least one central unit designating said first password code as a current password code, a method of controlling access to the two-way communication system characterized by the steps of: in at least one of said plurality of subscriber units: (a) transmitting at least said call request code; (b) receiving a command code and generating a second password code in response thereto; (c) transmitting at least said second password code and said identification code; at said at least one central unit: (a) receiving at least said call request code; (b) transmitting said command code; (c) receiving at least said second password code.
Claim 8
Dependent Claim
42 words
The method of claim 5, which includes the central unit step of: (c1) storing said second password code, and operating thereafter using said first password code as a previous password code, and using said second password code as a current password code.
Claim 9
Dependent Claim
17 words
The method of claim 5, which includes the subscriber step of: (d1) receiving a channel grant code.
Claim 10
Dependent Claim
40 words
The method of claim 5, which includes the central unit steps of: (d) determining whether said second password correlates to a current password; (e) granting access to said two-way communication system if said second password correlates to said current password.
Claim 11
Dependent Claim
70 words
The method of claim 5, which includes the central unit steps of : (d) determining whether said second password correlates to a current password; (e) determining whether said second password correlates to a prior password; (f) granting access to said two-way communication system if said second password does not correlate to said prior password and does not correlate to said current password, else denying access to said two-way communication system.
Claim 12
Dependent Claim
75 words
The method of claim 5, which includes the central unit steps of: (d) determining whether said second password correlates to a current password; (e) determining whether said second password correlates to a prior password; (f) granting access to said two-way communication system when said second password correlates with said current password ore does not correlate to said prior password and does not correlate to said current password, else denying access to said two-way communication system.
References Cited (Backward Citations)
No citation records indexed.
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