Abstract: A fan controller reduces the percentage of time that fans used in a heat exchanger of an outdoor cabinet that houses electronics and power source must operate to provide required cooling to the electronics and power source. The fan controller can also reverse operation of a fan of the heat controller to help reduce clogging of air intakes as well as to clean the interior of the cabinet. In an embodiment, the controller operates the fans in the heat exchanger according to operating temperature ranges. Thermostats can be used to provide the operating temperature ranges. Depending on the state of the thermostats and the ambient temperature, the fan controller causes one fan to operate in the reverse direction while the other fan is idle, causes one fan to operate in the forward direction while the other fan is idle, or causes both fans to operate in the forward direction.

Abstract: An adaptive unit that taps into an existing POTS line, DLC POTS line, DLC channel unit designed for sealing current outputs, or AC-DC transformer designed for sealing current output, to provide sealing current to a DSL circuit thereby avoiding having to deploy a separate sealing current unit to supply the desired sealing current to the DSL circuit. The adaptive unit, or sealing current derivation device, is preferably deployed at remote terminals thereby facilitating the offering of new DSL service, but may also be utilized in a central office.