GAOTek Compact Telecom Line Tester

This compact Telephone Line Tester adopts CPU, IC and SMT technology and is used for line maintenance and construction with insulation test distance upto 1.24 mi (2 km)



GAOTek Compact Telecom Line Tester uses CPU, IC and SMT technology and adopts and this portable, intelligent line fault tester is used for line maintenance and construction with insulation test distance upto 1.24 mi (2 km). It integrates various functions such as telephone set, circuit performance tester and security tester. The incoming call number display function is compatible with FSK and DTMF meeting the GB/T 15279-94 standard. The tester can perform multi-line as well as twisted pair testing. It also features low voltage warning and auto power off for energy savings.

Key Features

  • Insulation test distance upto 1.24mi (2km)
  • FSK/DTMF compatibility
  • High voltage alarm
  • DTMF meets GB/T15279-94
  • Number dialed display, Caller ID display
  • Wire pair check
  • Low voltage warning, auto power off
  • Compact and simple to operate
  • LCD screen to display line voltage
  • Chargeable 9 V Ni-MH battery
  • High resistance monitoring
  • Mute function

Technical Specifications

DC Voltage Range 0 V to 260 V

Error: ±5 %

Standards GB/T15279-94
Insulation Test Range 0 MΏ to 40 MΏ, two level display
Ring up User Distance ≤ 1.24 mi (≤ 2 km)
Line Break Test Distance ≤ 1.24 mi (≤ 2 km)
Monitor Resistance  ≥ 1 MΏ
Battery Chargeable 9 V Ni-MH battery
Dimension 9.14 in x 2.88 in x 3.80 in (232 mm x 73 mm x 95 mm)
Weight 1.102316 lbs (0.5 kg)
Relative Humidity 10 % ~ 95 %
Environment Noise ≤ 60 dB
Atmospheric Pressure kpa 86 kpa ~106 kpa
Storage Temperature 14 ˚F to 131 ˚F (-10 ˚C to + 55 ˚C)



  1. The telephone line tester shell
  2. Belt clamp – use it to hung tester in tool belt of waist or cable
  3. Terminal box – operate with assistant test line
  4. Test clamp
  5. Charge jack
  6. Headphone jack
  7. Assistant test line – operate with terminal box
  8. Charger
  9. Assistant line of checking wire pair function

Front Faceplate:

  1. HOOK
  2. P…T – “*” and P/T
  3. LCD – Display telephone number and test result
  5. MUTE
  6. Dial key – 1……9,*, #
  7. H-DCV LED indicator – If there is high DC voltage (70 V< voltage < 250 V) on the line, the indicator will be ON
  8. Charger LED. This light will be on when the tester is charging
  9. H-ACV LED indicator – If there is high AV voltage on the line, the H-ACV indicator will be lighted
  10. Talk indicator light. This light will be bright when talking

Tester Faceplate

  1. Phone/Tester – Press the key to enter “test status”; loose the key to enter “telephone status”
  2. Talk – Talk to user
  3. Call MΩ – Call user
  4. Mon – Monitor status

Operation Directions:


LED is ON by pressing “HOOK key” to talk and there will be a sound to dial number. To end talk press “HOOK key”.


Press “HOOK key” to talk when the tester is ringing. To end talk press “HOOK key”.


Press “REDIAL”, and redial the last telephone number. If it is busy, please hang and press redial again.

Incoming call number display:

This function is only used in the line which has incoming call number display service and the function can check the line repair quality, the incoming call number will be displayed when it receives the FSK or DTMF incoming call. The number can be refreshed automatically.

If the incoming call number is secret and it will be displayed as:

If the size of incoming call number exceeds the range and it will be displayed as:

If the incoming call signal is wrong and it will be displayed as:

Mute function:

Connect clamps to the telephone line, press Hook and then press “MUTE”, the other side cannot hear our voice, and press “MUTE” again, it becomes normal.

High DC voltage indication:

Connect this tester to the telephone line, if there is high DC voltage, the H-DCV light will be bright all the time. Do not off-hook to damage the tester.

Tester test:

AC V & DC V Test:

  • In the normal status, press “Phone/Tester” (“Phone/Tester” LED on) to have the voltage test.
  • If there is high AC voltage in the line the LCD display like following and there is fluting sound. Remove the clamp quickly.

  • The LCD will display the line voltage value automatically if there is DC voltage in the line.


This function can be used to test whether the ringing up/off voltage of line is normal or not; it can help lineman to distinguish the positive port and negative port of the line quickly.

Insulation Test:

  • Press “Phone/Tester” in the normal status to judge there is no voltage in the line, and keep pressing “Test” about 3 seconds to test the insulation. The LCD will display the insulation resistance figure automatically.

  • If the insulation resistance is less than 10MΩ and there is the fluting sound, it means the insulation resistance figure of the line is in small side and there is bad insulation fault.

Earth Insulation:

Connect the black clamp to earth line and the red clamp to the test line. The LCD will display the earth insulation degree.

Check wire pairs

  • Fix the side A and side B in normal communication status from the agreed line.
  • The man in the side A tell the man in the side B which line links with the red clamp, and make this line as assistant line.
  • The man in the side B twist one of the checking lines with the assistant line and keep on communicating the status with side A.
  • Then, the man in the side A use the assistant line C which insert into the charge hole to touch the core line one by one, until both sides hear the flute sound .
  • Repeat the process by checking the other lines in the similar way.

High AC voltage detect and alarm

Press the “Phone/Tester” and then press the monitor (“Mon”) .When the tester is near the line circuit which has high AC voltage; Monitor LED is on and there is alarm sound. Take care and operate it carefully.

Purpose: The safety of the line can be tested before by using this function and to avoid the danger effectively.


  • The charger LED is ON after inserting the output plug of charger into charge hole and the charger into 220V socket.
  • The duration of charging is 8 to 10 hours.
  • Do not press “Phone/Tester” during the charge process; if pressed there will be the fluting sound.
  • If the tester is not used for a long time, charge it full for storage, and charge the tester every 30 days.


Reference values of duration time under different status as below:

180mAH  NI-MH battery Theoretic service time Actual use time
Standby Time 80 days More than 30 days
Talkback 4 hours More than 2.8 hours
Insulation Test 3 hours More than 2.7 hours
Voltage test 10 hours More than 8 hours
Induction Voltage 5 hours More than 4.4 hours
Monitor 18 hours More than 15 hours


  1. Main test line
  • The soft test line has the terminal box and special clamp.
  • When the voltage is tested, the red line is the anode and the black line is cathode.
  • To test using the special clamp of main test line connect every kind of telephone line.
  1. RJ11 linking line

It can be inserted into the socket in the wall or used to test the telephone line through terminal box.


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