# US 10,121,362 B1 · Networked electronic article surveillance systems with synchronized tracking > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,121,362 B1 - Document ID: US10121362B1 - Status: Granted - Kind: B1 - Application number: 15/677,556 - Filed: 2017-08-15 - Granted: 2018-11-06 - Earliest claimed: 2017-08-15 - Assignees: Tyco Fire & Security GmbH - Applicants: Adam S. Bergman; Manuel Soto; Michael Del Busto - Inventors: Adam S. Bergman; Manuel Soto; Michael Del Busto - Web page: https://patentgrep.com/patent/US10121362B1 ## CPC - G08B 29/185: {Signal analysis techniques for reducing or preventing false alarms or for enhancing the reliability of the system} - G08B 13/2402: {Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting (mechanical aspects of the tags, e.g. related to locking E05B73/0017; RFID readers G06K7/00; RFID tags G06K19/00; access control systems G07C9/00; anti-theft control in point of sale systems G07G3/003; security seals G09F3/03)} - G08B 13/2488: {Timing issues, e.g. synchronising measures to avoid signal collision, with multiple emitters or a single emitter and receiver} - H04W 56/00: Synchronisation arrangements - G08B: SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Systems and methods for operating an Electronic Article Surveillance (“EAS”) system. The method comprising: receiving, by an electronic device, a synchronization signal transmitted from a remote Wireless Device Manager (“WDM”); performing first transmit and receive operations at the electronic device that are synchronized in accordance with the remote WDM's AC power line zero crossing specified by the synchronization signal; detecting when the synchronization signal is no longer being received by the electronic device; and performing second transmit and receive operations at the electronic device that are synchronized in accordance with the electronic device's local AC power line zero crossing, when the synchronization signal has not been received by the electronic device for a specified period of time. ## Claims ### Claim 1 A method for operating an Electronic Article Surveillance (“EAS”) system, comprising: receiving, by an electronic device, a synchronization signal transmitted from a remote Wireless Device Manager (“WDM”); performing first transmit and receive operations at the electronic device that are synchronized in accordance with a zero crossing of an AC power line supplied to the remote WDM; detecting when the synchronization signal is no longer being received by the electronic device; determining a delta value between a first time at which the zero crossing of the AC power line supplied to the remote WDM occurred and a second time at which a zero crossing of an AC power line supplied to the electronic device occurred; converting the delta value into a delay value using a third time at which another zero crossing of the AC power line supplied to the electronic device occurs; and performing second transmit and receive operations at the electronic device that are synchronized in accordance with the delay value, when the synchronization signal has not been received by the electronic device for a specified period of time. ### Claim 2 (depends on 1) The method according to claim 1, wherein the electronic device comprises an EAS detection system or a WDM other than the remote WDM. ### Claim 3 (depends on 1) The method according to claim 1, further comprising logging a receive time at which the synchronization signal is received by the electronic device. ### Claim 4 (depends on 3) The method according to claim 3, further comprising using the receive time to determine the first time at which the zero crossing of the AC power line supplied to the remote WDM occurred taking into account known transmission delays. ### Claim 5 (depends on 4) The method according to claim 4, further comprising determining the second time at which the zero crossing of the AC power line supplied to the electronic device occurred. ### Claim 6 (depends on 1) The method according to claim 1, further comprising detecting when the synchronization signal is once again being received by the electronic device. ### Claim 7 (depends on 6) The method according to claim 6, further comprising performing third transmit and receive operations by the electronic device that are synchronized in accordance with the synchronization signal, when the synchronization signal is once again being received by the electronic device. ### Claim 8 A system, comprising: a processor; and a non-transitory computer-readable storage medium comprising programming instructions that are configured to cause the processor to implement a method for operating an Electronic Article Surveillance (“EAS”) system, wherein the programming instructions comprise instructions to: receive a synchronization signal transmitted from a remote Wireless Device Manager (“WDM”); perform first transmit and receive operations that are synchronized in accordance with a zero crossing of an AC power line supplied to the remote WDM; detect when the synchronization signal is no longer being received by the system; determine a delta value between a first time at which the zero crossing of the AC power line supplied to the remote WDM occurred and a second time at which a zero crossing of an AC power line supplied to the electronic device occurred; converting the delta value into a delay value using a third time at which another zero crossing of the AC power line supplied to the electronic device occurs; and perform second transmit and receive operations that are synchronized in accordance with the delay value, when the synchronization signal has not been received by the system for a specified period of time. ### Claim 9 (depends on 8) The system according to claim 8, wherein the system comprises an EAS detection system or a WDM other than the remote WDM. ### Claim 10 (depends on 8) The system according to claim 8, wherein the programming instructions further comprise instructions to log a receive time at which the synchronization signal is received by the system. ### Claim 11 (depends on 10) The system according to claim 10, wherein the programming instructions further comprise instructions to use the receive time to determine the first time at which the zero crossing of the AC power line supplied to the remote WDM occurred taking into account known transmission delays. ### Claim 12 (depends on 11) The system according to claim 11, wherein the programming instructions further comprise instructions to determine the second time at which the zero crossing of the AC power line supplied to the electronic device occurred. ### Claim 13 (depends on 8) The system according to claim 8, wherein the programming instructions further comprise instructions to detect when the synchronization signal is once again being received by the system. ### Claim 14 (depends on 13) The system according to claim 13, wherein the programming instructions further comprise instructions to perform third transmit and receive operations by the system that are synchronized in accordance with the synchronization signal, when the synchronization signal is once again being received by the system.