| 摘要 |
<p>Power Sourcing Equipment (PSE) provides a PoE supply voltage over data wires (12,13) to a Powered Device (PD). A PSE controller controls a first FET (FET1) that couples the PoE voltage to the data wire pairs (12,13) and controls a second FET (FET2) that couples the data wire pairs (12,13) to the spare wire pairs (14,15). Upon powering up, the PSE controller keeps the two FETs open and performs a detection routine on any devices connected to the data pairs (12,13) and spare pairs (14,15). If a PoE-compatible PD is detected as being coupled to the data pairs (12,13), the first switch (FET1) is closed. If it is determined that the PoE voltage should also be coupled to the spare pairs (14,15), the second FET (FET2) is also closed. The method prevents the PoE voltage from being applied to the spare pairs (14,15) when the device connected to the spare pairs (14,15) is not PoE compatible and maintains backwards compliance with IEEE PoE PDs.</p> |
