Lightning protector for sensitive/off-premise eqpt (modems, phones, telemetry)

Description

The Cambridge Electronics Laboratories Off-Premise Multi-Protector is designed to enhance the survivability of a telecom device connected to a single copper pair which may be exposed to a.c. induction, lightning or power cross, typically an off-premise extension from a PBX, Key System or Automatic Ringdown Unit (hotline device).  Effective protection requires a properly installed ground and even so 100% survivability is not assured due to the power levels involved in e.g. a direct lightning strike.  However the Off-Premise Multi-Protector will greatly enhance the survivability of telecom devices connected to exposed lines.
The Off-Premise Multi-Protector enhances survivability by utilizing three component types.
* Gas tubes to divert majority of energy to ground; these highly reliable devices will survive a lightning strike but allow a remnant of the potentially damaging energy to pass by.
* Varistors to absorb the entire remnant energy and/or divert to ground.  Unless themselves protected these devices may fail.
* Thermistors to protect the varistors.
Used together these three types of components protect both each other and a connected telecom device.