Using a buttset

Using a buttset
The buttset (or butt set) is one of the most versatile and important pieces of telephone test equipment.

Some older phone guys call them "buttinskys." Some manufacturers call them "test sets." People outside the phone biz often call them "lineman's phones."

But in the biz, and on this website, they're "buttsets."

No one seems to be sure why a buttset is called a buttset. Maybe because it can be used to "butt-in" to a conversation ("buttinsky"), maybe because it's usually hung from a tool belt on a phone geek's butt, or maybe because phone geeks use them while sitting on their butts.

The nickname may also relate to a buttset's ability to make a temporary connection by "butting" its clips against phone wires or screws. (A "butt splice" connector secures the ends of two wires that are touching each other. A "butt joint" is a carpentry technique in which two pieces of wood are joined by "butting" them together.)

While some buttsets now have LCD displays, and the number of buttons grows with each new generation, the fundamental functions of the buttset has been the same for about 100 years -- to enable you to determine if a line is live or dead, to isolate trouble, to identify a phone line, and to make and receive calls.

Basically, a buttset is a one-piece telephone, usually equipped with cords ending in alligator clips that can be quickly attached to wires, screws, and various terminals. In many tests, it acts as a substitute for a normal phone. so you can compare conditions to identify the source of trouble.

If you need to connect your buttset to a phone or data jack, our Modapt (at left) makes it easy. It works with 4-, 6-, and 8-conductor jacks because it comes with an amazing universal test cord with plugs that fit into all jack sizes. There are two built-in jacks for inline testing. A stainless steel clip on the back makes it easy to keep the Modapt with your buttset -- just clip it to the test cords. USOC, T568A, and T568B wiring charts are printed right on the Modapt body for quick reference.



Here are some things to do with your buttset:

  • A phone is dead. Is it the fault of the phone or the wiring? Unplug the phone. Connect your buttset's clips to a Modapt and plug it into the jack, or open up the jack and connect the buttset clips to the screws inside the jack (not all jacks have screws). If you can make and receive calls with the buttset, but not with the regular phone, the phone is NG. This procedure is for basic analog phones only. If you connect your buttset to a digital line, you may hear a tick-tick-tick sound, or just hear your own voice coming back to you, but there won't be any dialtone or ringing, and you won;t be able to make calls.


  • A line is noisy or dead. Is it the fault of connected equipment, or the phone company?
  • Go to the network interface, sometimes called the "demark." (It's a connection point between the phone company, and the privately-owned phone equipment.) Disconnect the private equipment. Connect the buttset to the incoming line. If you hear dial tone, and can make a call with no background noise, you know it's not the phone company's fault.

  • What's the phone number here? When the phone company installs several phone lines, very often they don't tag them or label them with phone numbers, which can make it difficul to connect the lines in the proper sequence to a phone system, or to report trouble when a line malfunctions. Most phone companies have secret "Automatic Number Announcement" (ANA) numbers that can be called, so a robot will tell you the number you are calling from. Sometimes, a friendly phone man will tell you the number for your area, but these numbere tend to change fairly often. Verizon has used 990, 990-1111 and 958. SBC-SNET used 970#, but it changed to 959-9822 after the AT&T takeover. 800 444-444 provides number announcements, but maybe only for MCI customers. Just connect your buttset, verify that you have dialtone, dial the ANA number, and write it down.


  • How can I listen to my sister talking to her boyfriend? Connect the buttset to wires or another jack connected to your sister's phone line. Switch the buttset to the "monitor" mode, or use the speakerphone in the "mute" mode, so she won't hear you laughing.