>>Application background:           
1.RS485/232 take a long line, vulnerable to over voltage           
2.RS485/232 line in the outdoor, vulnerable to lightning           
3.RS485/232 is easy to be disturbed by other signals        

 >>Program description and notes:           
1 Front end uses a large flow of GDT, leakage current.           
2 Back end using fast response time of TVS to clamp the voltage to low level, effectively protect the RS485/232 controller.           
3 In the middle part of circuit to use PTC for decoupling, let the front end GDT action easily for discharge current.           
4 This scheme meets the standards of IEC61000-4-2, GBT17626.2 and other static standards, such as IEC61000-4-5, GBT17626.5 and so on.          
5 The same TVS and GDT are used in both modes of the differential and common in this program, and no protection dead angle           

6 Meet 10/700uS (40ohm equivalent resistance) 1.2/50uS and 8/20 standards.       


>>Program application:           
1 Surveillance / Security system           
2 Entrance guard system             
3 Railway signal control lamp           
4 Intelligent Transportation Systems           
5 Meter / meter instrument           

6 Optical switch/converter/tranceiver        


>>Protection circuit diagram and product appearance:

>>PulseTake Protection Device
2 GDT: PTC471N (Mid-level lightning protection)    PWF471N(High-level lightning protetction)
3 PTC1/PTC2: P250-120

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