Main functions and features1. Dial, Talk and Receive calling( As normal telephone)2. Monitor3. Identify ADSL/ISDN service4. Storage phone number5. Tone/Pulse dialing mode switch6. Pause7. Redial8. Mute9. Polarity identify10. Adjust the volume11. Inside rechargeable batteryPackage Including1 X Intelligent Telephone Line TesterApplication: Part Number: ST230EST230E Line Tester as amulti-functional tester, due to the dumbbell shape, it can be put on theshoulder during operation, which can enable the operator to deal withother work conveniently at the same time. What is more, the operator caneven go climbing as it can be hung in the tool belt of waist by thepothook. Regarding the material of shell, it can be waterproof(IP41),dustproof, anti-break and enjoys high reliability.