ST200 pocket-sized smart to check the line instrument on the basis of the ordinary telephone, to increase the barriers to testing, self-ringing, call the user on the line, redial, P / T-conversion and high-voltage protection function, effectively reduces the line maintenance personnel the workload of the rugged line maintenance personnel to open and maintain an ideal tool for related businesses. 
 Introduction 
 Telephone functions: with an ordinary phone, connected to the telephone line has a dial, call, closing bell function. 
 , Barriers to testing capabilities: the test line in the passive test users online, can carry out the insulation test gas to test and break tests. 
 , Call and intercom user: test line connected to the passive test users online, you can ring the user telephone, pursuant to verify the repair of the line. 
 4 line intercom function: The ST200 (called party) and any check-ray machine (called B) to complete the work on the line through the intercom. 
 5, the DC high voltage protection. 6P standard interface 
 Technical indicators 
 A 0-10MΩ fourth gear indication of the resistance of the insulation test. 
 Ringing call distance: ≤ 1KM. 
 3, break-resolved distance: ≤ 3KM. 
 4, dial indicators to meet the the GB/T15279-2002 requirement. 
 5, DC protection voltage: 60V-300V. 
 6, Power: 9V battery. 
 7, volume: 146mmх54mmх37mm,. 
 8, Weight: ≤ 220g.