| 摘要 |
A powered device, such as an IP telephone, includes power converter electronics that allows the powered device to couple to multiple power sources and receive a relatively large amount of power (e.g., 15 W or greater) from any single power source or from any combination of the power sources. For example, the powered device can connect to a first power source and a second power source by a cable having four twisted pairs of conductors where a first two-pair set of conductors couples the powered device to the first power source and a second two-pair set of conductors couples the powered device to the second powered device. In use, the converter circuitry can provide power to the load from either the first power source via the first two-pair set of conductors, the second power source via the second two-pair set of conductors, or from both power sources via both the first and second two-pair sets of conductors.
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