A lineman's handset is a special type of
telephone
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into e ...
used by
technician
A technician is a worker in a field of technology who is proficient in the relevant skill and technique, with a relatively practical understanding of the theoretical principles.
Specialisation
The term technician covers many different speciali ...
s for installing and testing
local loop
In telephony, the local loop (also referred to as the local tail, subscriber line, or in the aggregate as the last mile) is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the commo ...
telephone line
A telephone line or telephone circuit (or just line or circuit industrywide) is a single-user circuit on a telephone communication system. It is designed to reproduce speech of a quality that is understandable. It is the physical wire or ot ...
s. It is also called a test set, butt set, or buttinski.
Components
A typical lineman's handset integrates an earpiece, a mouthpiece, a
dialing interface, and a set of test leads for connecting to the telephone circuit. Originally, lineman's handsets featured a
rotary dial
A rotary dial is a component of a telephone or a telephone switchboard that implements a signaling technology in telecommunications known as pulse dialing. It is used when initiating a telephone call to transmit the destination telephone number ...
, but modern sets use some variant of the standard 12-button
DTMF
Dual-tone multi-frequency signaling (DTMF) is a telecommunication signaling system using the voice-frequency band over telephone lines between telephone equipment and other communications devices and switching centers. DTMF was first developed ...
keypad
A keypad is a block or pad of buttons set with an arrangement of digits, symbols, or alphabetical letters. Pads mostly containing numbers and used with computers are numeric keypads. Keypads are found on devices which require mainly numeric in ...
and also employ an amplifier for speaker use. Most handsets are designed to be used with analog "
POTS" lines, and have limited or no function with
digital circuits
Digital electronics is a field of electronics involving the study of digital signals and the engineering of devices that use or produce them. This is in contrast to analog electronics and analog signals.
Digital electronic circuits are usually ...
. Older Telephone linemen also referred to the Buttset as a "Goat".
In addition to the basic features listed above, handsets often include one or more of:
*
Speakerphone
A speakerphone is a telephone with a microphone and loudspeaker provided separately from those in the handset. This device allows multiple persons to participate in a conversation. The loudspeaker broadcasts the voice or voices of those on the ot ...
* Redial
* A talk/monitor
toggle switch
In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of ...
* Mute
*
Hook flash On analog telephone lines with special services, a flash or register-recall signal is used to control functions on the public telephone exchange, PBX or VoIP ATA.
The term "register-recall" in Europe refers to sending a discrete signal to alert t ...
button
*
Tone/
pulse dialing
Pulse dialing is a signaling technology in telecommunications in which a direct current local loop circuit is interrupted according to a defined coding system for each signal transmitted, usually a digit. This lends the method the often used name ...
selection switch
*
Low-pass filter
A low-pass filter is a filter that passes signals with a frequency lower than a selected cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency. The exact frequency response of the filter depends on the filt ...
ing to prevent disruption of data communications (such as
DSL
Digital subscriber line (DSL; originally digital subscriber loop) is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric dig ...
)
* A mechanical hook for hanging the set from a
tool belt. On some sets, it may be moved to the receiver side, mouthpiece side, or removed altogether.
Typical use
A lineman's handset typically connects via a pair of test leads, not the
modular connector
A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such as in computer networking, telecommunication equipment, and audio headsets.
Modular connectors were originally developed fo ...
found on most consumer telephone equipment. The test leads will feature some combination of
alligator clips (to connect to bare wires), a piercing spike or "bed-of-nails" (for insulated wires), and something designed to fit a
punch block
A punch-down block (also punchdown block, punch block, punchblock, quick-connect block and other variations) is a type of electrical connection often used in telephony. It is named because the solid copper wires are "punched down" into short open ...
.
Adapter
An adapter or adaptor is a device that converts attributes of one electrical device or system to those of an otherwise incompatible device or system. Some modify power or signal attributes, while others merely adapt the physical form of one c ...
s designed to fit other punch block types,
heat coil
Heat coils, also known as ''protectors'', ''bugs'' or ''carbons'' serve as a surge protector between the telephone exchange and outside plant. They are commonly the last point of appearance for a telephone circuit before it leaves the office, for ...
sockets, or modular jacks may also be used.
A butt set can be connected wherever there is a
line appearance—anywhere the wires are accessible. Inside the
central office, this would be at a
main
Main may refer to:
Geography
* Main River (disambiguation)
**Most commonly the Main (river) in Germany
* Main, Iran, a village in Fars Province
*"Spanish Main", the Caribbean coasts of mainland Spanish territories in the 16th and 17th centuries
...
or
intermediate distribution frame
An intermediate distribution frame (IDF) is a distribution frame in a central office or customer premises, which cross connects the user cable media to individual user line circuits and may serve as a distribution point for multipair cables fr ...
. For
outside plant
In telecommunication, the term outside plant has the following meanings:
*In civilian telecommunications, outside plant refers to all of the physical cabling and supporting infrastructure (such as conduit, cabinets, tower or poles), and any associ ...
, this would include any
serving area interface
The serving area interface or service area interface (SAI) is an outdoor enclosure or metal box that allows access to telecommunications wiring.
Alternate names
*Access point (AP)
*Cabinet (cab)
*B-box (breakout box)
*Cross box
*Cross-connect b ...
, such as a
cross-connect box
A digital cross-connect system (DCS or DXC) is a piece of circuit-switched network equipment, used in telecommunications networks, that allows lower-level TDM bit streams, such as DS0 bit streams, to be rearranged and interconnected among highe ...
or aerial splice enclosure. At subscriber sites (e.g., residence), this could be inside or behind the housing of a modular connector, or at the
network interface.
When connected to a line, a lineman's handset is essentially indistinguishable from regular
subscriber equipment. The technician can do one or more of monitor an active call, answer incoming calls, and make outgoing calls. Common tests include checking for
dial tone
A dial tone is a telephony Signaling (telecommunication), signal sent by a telephone exchange or private branch exchange (PBX) to a terminating device, such as a telephone, when an off-hook condition is detected. It indicates that the exchange is ...
, using
ANAC to identify the line, and using a
ringback number
A ringback number is a telephone number for a telephone line that automatically calls the line that the call was placed from, after the caller has hung up. The typical use of this facility is by telephone company technicians for testing a new insta ...
.
See also
*
Beige box (phreaking)
References
External links
{{Commonscat, Lineman's handset
Telephony equipment