Patent ID: 8627127

Claim:
A thermostat, comprising: a plurality of heating, ventilation, and air conditioning (HVAC) connectors including a common wire connector and at least one call relay wire connector; a rechargeable battery; a power stealing circuit configured to provide electrical power for use by the thermostat and for charging the rechargeable battery at least in part by stealing power from at least one call relay wire coupled to said at least one call relay wire connector such that said electrical power can be provided and said rechargeable battery can be recharged without requiring a common wire to be coupled to said common wire connector; a processor powered at least in part by the rechargeable battery, wherein: the processor is configured to operate in a low-power state; and the processor is configured to operate in a high-power state; a wireless communication module operatively coupled to the processor and configured to: establish and maintain wireless communications with a router, including receiving transmissions from the router; process the transmissions from the router by discriminating between a first type of transmission and a second type of transmission, wherein: the first type of transmission comprises keep-alive messages associated with a communication channel between a remote thermostat-controller server and the thermostat, and the second type of transmission comprises information associated with controlling the HVAC system; in response to identifying a transmission of the second type during a time period in which the processor is operating in the low-power state, causing the processor to transition from the low-power state to the high-power state; whereby the processor can operate in the low-power state for an extended period of time while a Natural Address Translation (NAT) table entry in the router that is associated with said communication channel between the processor and the remote thermostat-controller server remains maintained during said extended period of time.