Patent Number: 6,169,492

Title: Remote keyless entry user-transparent auto re-synchronization apparatus and method

Abstract: A method of user-transparent auto re-synchronization for a remote keyless entry system includes assigning a default challenge-count window (101). A first data packet including a first transmitter-side symbolic count (103) and a first command code is transmitted by a transmitter (200) and authenticated by a receiver (250). An auto-synchronization challenge-count window is assigned when the first transmitter-side symbolic count (103) is not bounded within the challenge-count window (109). A second data packet including a second transmitter-side symbolic count (103) and a second command code is transmitted by the transmitter (200) and authenticated by the receiver (250). The challenge-count window is returned to the default challenge-count window, when the second transmitter-side symbolic count is bounded within the auto-synchronization challenge-count window and the receiver-side symbolic count (123). Then the second command code is executed (127).

Inventors: Dabbish; Ezzat (Cary, IL)

Assignee: Motorola, Inc.

International Classification: B60R 25/00 (20060101); G07C 9/00 (20060101); G06F 007/04 ()

Expiration Date: 01/02/2018