Embodiments are directed to a transient protection circuit configured for use in a SSPC having a plurality of power channels. The transient protection circuit includes a shared transient voltage suppressor, and a shared protection line communicatively coupled to the shared transient voltage suppressor. The shared protection line is configured to be communicatively coupled to and shared by the plurality of power channels. When the shared protection line is communicatively coupled to and shared by the plurality of power channels, energy above a threshold on any one of the plurality of power channels is dissipated through the shared protection line and the shared transient voltage suppressor.

A new POE & cable tester with BT standard test, including an interface module, a network transformer, a rectifier module, a power management module, and at least one optocoupler detection module, in which the interface module is connected to a primary coil, a secondary coil output end of the network transformer is connected to a line testing module, a center tap of the network transformer is connected to the rectifier module, the power management module is connected to an output end of the rectifier module, the power management module is connected to at least one optocoupler detection module, and the optocoupler detection module is connected to a data end of a central control module. The present disclosure is introduced based on the market demand for testing IEEE 802.3bt standard POE switch, which allows testing IEEE 802.3bt standard POE switch standard, and allows screening of POE switch standard with RJ45/RJ11 connector.