ST230 Tel Line Tester is one portable and intelligent line fault tester, which adopts advanced technologies such as intelligent CPU, IC & SMT technology. It integrates various kinds of functions such as telephone and line performance test to be the one. The incoming call number display function is compatible with FSK/DTMF two types. Its particular function of DC/AC voltage test can test whether there is dangerous DC/AC high voltage in the line or not quickly and accurately in order to protect lineman from high voltage. The tester is designed following the human engineering theory with the appearance style like barbell, it can be put on the shoulder, the lineman can do other work using hands at the same time; Besides, it can be hung in the tool belt of waist through the pothook, it is convenient to realize the talk function cooperate with the high quality earphone when the lineman is climbing or doing other things; The max working duration when the inside rechargeable Ni-MH battery is fully charged is 7 hours; The shell is made of the new type of material and it resists water and shock. FEATURES 1. CID function, FSK/DTMF compatibility 2. DTMF applying to GB/T15279-94 3. Dialing number display 4. Checking wire pairs function 5. Low voltage warning, automatic power off and energy-save design 6. Small size, simple operation