Do not use your tester, phone, TTY, or computer during a thunderstorm.

It is recommended that you try out the tester as soon as you get it to familiarize yourself with the sound sequences your phone company uses. You may need to get a hearing person to help the first time you use the tester. They can help you distinguish between the different sounds.


Insert appropriate batteries in the battery compartment.

Turn on the power switch. Most speakers have a pilot light to indicate that they are on. If the pilot light does not come on, try replacing the batteries.

If equipped, turn the volume control to high, usually clockwise.

Place your finger lightly on the speaker cone.

Plug in the phone cord.

If equipped, turn on the phone line switch.

Sound Sequences

Please note. Your phone company may not use the following sequence of sounds. This is why you should try to have a hearing person present when you first try your tester, so they can point out any differences.

When everything is working properly the first sound that occurs is the dial tone. This is a steady smooth frequency. The dial tone usually continues for around 20 seconds depending on your phone system.

If a number is not dialed during this time, the system will first disconnect the line for about ¼ second, then 1 or 2 rings sound, then a recording comes on. The most common recording is "If you'd like to make a call, please hang up and try again. If you need help, hang up and then dial your operator." This message is repeated a second time. The purpose of the disconnect is to allow for some phone equipment that may have been placed on hold to release the line and reset. This disconnect will make the LED on your tester blink off for ¼ second. If you see this blink, it will help you to better understand where you are in the sequence. Note that a few phone systems do not have this feature.

Next there is a pause of about 15 seconds, then a very loud pulsating screech for about 45 seconds. This is to alert hearing people that they have a receiver off the hook. This sound can usually be heard for quite a distance throughout the house or office.

At this point all sound ceases and there is just silence on the line. The DC current continues to be present indefinitely. Your LED should remain lit.

If you go on hook (hang up), or disconnect the tester, the system should reset itself.

If you are on a normal call and the person or machine on the other end of the line disconnects, without you disconnecting, the entire sequence above will begin in about 15 seconds. Note that some phone systems will not release the connection if only one party disconnects.

If there is a short in your phone line (2 wires touching) or a piece of equipment does not hang up the line, the above sequence will be performed and then the line will go silent with a DC current until the short is fixed or the defective piece of equipment is disconnected. Note that if a short is present the LED may glow only dimly or may not light at all. If the LED does not light see the conditions section below.

Under certain vary rare conditions, if a system damaging fault has occurred, (such as a high voltage current getting into the phone line) the phone company's equipment may automatically disconnect the line completely. Correcting the problem will usually reset the system, however a call to the phone company may be needed.


Point to remember. As long as your tester is connected to the phone line and (if equipped) the line switch is on, your phone line is in an off hook condition

If the phone line has a DC voltage present, meaning the line is working, one of the LEDs on the tester will glow. It doesn't matter which one.

You should be able to feel any sounds on the phone line.

If you get a lit LED, but no sound, this indicates the phone line is in an off hook condition meaning a phone or device, such as a modem or TTY, is off hook.

If the LED does not light, either the jack you are connected to is dead, there is a short (2 wires touching), or the phone line is dead.

IF the LED does not light at a jack in the house, the first thing to do is go to the telephone company's interface box. >This is usually a small gray box, about 6 inches square, near your electric meter or fuse panel.

Open the section labeled user or owner access.

You will see at least 1 very short (2 or 3 inches) gray or black cord that looks like the wire that connects your TTY or modem to the wall.

The end of this wire will have a modular phone plug on it.

Unplug the short cord and plug your tester into the jack. If the LED still does not light, check the Unusual Situations page. If you do not fall into one of the unusual situations, you need to call your phone company.

If the tester works at the interface box but not inside the house, you have a fault in your inside wring, or a piece of equipment causing the problem.

First try disconnecting all phone equipment in the house, then test the jack. If the jack now works, reconnect one piece of phone equipment at at time, rechecking the line after each item is hooked up until you find the problem device. Keep in mind the possibility of such situations as a modem or TTY that may be stuck in an off hook condition. Unplugging them may unstick them and they may not re-stick until the next time you actively use the device.

If after disconnecting all phone equipment the problem is still present, you have a wiring problem.


If you have the optional coupler and alligator clip leads, you can check for bad phone cords and trouble shoot in-wall wiring.

To check a bad phone cord, first check to make sure the wall jack is working properly. Then plug the tester into the coupler, connect the coupler to the suspect phone cord and plug the cord into the wall jack.

If you feel comfortable working on wires, you can plug the tester into one end of the coupler and the alligator clip adapter into the other end of the coupler. Remove the wall plate and clip the alligator clips to the wires.


The voltage across the phone wires (in the US) is 48 volts DC. You may get a strong tingle, but this is not enough to hurt you unless you have a pacemaker. However, the ringing voltage is 100 volts AC. If the phone should ring (someone calls you) while you are touching both conductors, you could be shocked. The amount of amperage involved however is very low, therefor even though you might be shocked, it is unlikely you can be injured unless you arm hits something as a result of jerking away from the wire.

If you have a short or an off hook condition, the phone system can not ring your line.

Happy trouble shooting