Abstract: A surge protection circuit includes a first surge absorber and a first conducting wire. The first surge absorber has an end electrically connected to a first power signal line. The first conducting wire is covered with insulating material and electrically connected to the other end of the first surge absorber and a second power signal line. The first surge absorber absorbs energy of a surge signal in a short-circuit state when the surge signal flows through the first power signal line or the second power signal line. Afterwards, the first conducting wire which is connected to the first surge absorber in series is damaged by the energy of the surge signal to enter an interrupted state, thereby protecting a signal processing device which is electrically connected to the first power signal line and the second power signal line.

Abstract: A surge-protected hub applied to set up an AC line networking system and used for eliminating the surge problem is provided. The surge-protected hub includes a housing; a plurality of connectors mounted on the housing and electrically connected to an alternating-current power source for independently establishing connections to power lines for power transmission or network lines for networking signal transmission; and a surge-protected device disposed in the housing and arranged upstream of the plurality of connectors for filtering out surge signals that are received from the alternating-current power source while allowing networking signals having a frequency range lying in the frequency range of the surge signals to pass therethrough.

Abstract: A surge protection circuit includes a first surge absorber and a first conducting wire. The first surge absorber has an end electrically connected to a first power signal line. The first conducting wire is covered with insulating material and electrically connected to the other end of the first surge absorber and a second power signal line. The first surge absorber absorbs energy of a surge signal in a short-circuit state when the surge signal flows through the first power signal line or the second power signal line. Afterwards, the first conducting wire which is connected to the first surge absorber in series is damaged by the energy of the surge signal to enter an interrupted state, thereby protecting a signal processing device which is electrically connected to the first power signal line and the second power signal line.

Abstract: A surge-protected hub applied to set up an AC line networking system and used for eliminating the surge problem is provided. The surge-protected hub includes a housing; a plurality of connectors mounted on the housing and electrically connected to an alternating-current power source for independently establishing connections to power lines for power transmission or network lines for networking signal transmission; and a surge-protected device disposed in the housing and arranged upstream of the plurality of connectors for filtering out surge signals that are received from the alternating-current power source while allowing networking signals having a frequency range lying in the frequency range of the surge signals to pass therethrough.

Abstract: A bi-directional low-pass filter for use at a user end or an office end in a communication network is disclosed. By providing compensation and high-band attenuation circuitry, the low-pass filter exhibits an improved attenuation value in high-band and a general attenuation value in a low-frequency band. The satisfactory attenuation performance in the high-frequency band minimizes the signal interference of a high-band communication terminal with a low-band communication terminal in the communication network. Further, by providing symmetric input/output circuitry, the low-pass filter can be operated reversibly.

Abstract: A bi-directional low-pass filter for use at a user end or an office end in a communication network is disclosed. By providing compensation and high-band attenuation circuitry, the low-pass filter exhibits an improved attenuation value in high-band and a general attenuation value in a low-frequency band. The satisfactory attenuation performance in the high-frequency band minimizes the signal interference of a high-band communication terminal with a low-band communication terminal in the communication network. Further, by providing symmetric input/output circuitry, the low-pass filter can be operated reversibly.

Abstract: A low-pass filter for use at a user end or an office end in a communication network is disclosed. By providing a capacitive compensation circuit for the low-pass filter, the low-pass filter exhibits an improved attenuation value in a high-frequency band and a general attenuation value in a low-frequency band. The satisfactory attenuation performance in the high-frequency band minimizes the signal interference of a high-band communication terminal with a low-band communication terminal in the communication network. On the other hand, the maintained attenuation value in the low-frequency band allows the low-pass filter to comply with the stipulations of a communication system, e.g. the performance criteria stipulated by TIE1.4.