The QDF product line includes a wide range of three-point protectors. Versions are available that utilise both gas tube and solid-state overvoltage protection, as well as hybrids.
QDF-3GCS-260 and QDF-3CGS-230 three-point protectors contain a heavy-duty, three-electrode gas discharge tube. They are used when frequent and large lightning-induced voltages are expected on the telecom pairs.
QDF-3CHY-200 and QDF-3CHY-260 three-point protectors have overvoltage surge protection devices that utilise both gas-tube and semi-conductor technologies. The products combine the high current-handling cabability of a gas-tube with the speed of a silicon device.