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Product Description

High voltage transients caused by lightning or other electrical disturbances have the ability to easily destroy semiconductor junctions, and thus, cause equipment failure. A lightning strike in the vicinity of data lines can cause induced ground currents which can also do serious damage. Typical leading edge wave-fronts of a lightning strike rise at the rate of 1,000 Volts per microsecond.

The Model 22 Lightning Sponge is designed to accommodate these transients, slow them down and redirect them to a low impedance path to earth ground.The Model 22 Lightning Sponge is a module that provides protection for four independent data communication circuits, operating at rates up to 38.4 KBPS, that may be exposed to such transients. The protection circuits incorporate 3 separate stages of limiting high voltage transients: gas tubes, avalanche diodes and MOV thyristors. The DC series resistance is limited to approximately 5 Ohms and the response time is measured in nanoseconds. A Model 22 should be installed on each end of the 4-wire transmission line for short haul modems or RS-232 devices.

The output voltage is limited to ±14 Volts for the Model 22, ±7.5 volts for the Model 22NX, and 180 Volts for the Model 22PX.The Model 22 and 22NX provides 4-wire screw terminals on both ends for terminating the 4-wire lines. The Model 22P provides modular RJ- 12 type phone receptacles for easy installation of the 4-wire lines. For all models, an additional screw terminal is provided to make the connection to earth ground. This wire should be at least #12 gauge or larger and be as short as possible. It will conduct the surge to earth ground (power ground or water pipe).

The first stage of protection is the gas tubes which are capable of accommodating 1,000 Amps. The output voltage is limited to ±14 volts for the Model 22 and 180 Volts for the Model 22PX.The Model 22NX is used to protect RS-422 based networks and includes 2 stages of protection.

Model 22: General Information

The Model 22 is packaged in a small aluminum enclosure whose size is 4.5"W (114mm) x 1.8"D (46mm) x 1.5"H (38mm)

22PX

The 22PX is designed to protect two wire dial-up modems. Therefore, all the protection levels have been changed to allow operation with ring voltages and higher DC levels used by the phone companies.

22NX

RS-422 is a low voltage, high speed interface. Protection of these RS-422 lines is accomplished by using the 4-wire Model 22NX. It limits the voltage to approximately 7.5 Volts and passes signals whose rates can exceed one million bits per second.

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