Telephone Set

Also found in: Dictionary, Thesaurus, Acronyms, Wikipedia.

telephone set

[′tel·ə‚fōn ‚set]
(engineering acoustics)
An assembly including a telephone transmitter, a telephone receiver, and associated switching and signaling devices. Also known as telephone.

Telephone Set


the apparatus used in a telephone-communication system mainly to transmit and receive vocal information. A telephone set generally comprises a handset with a transmitter and receiver and a separate housing with a switch hook, dial, and ringer.

Figure 1. Simplified circuit illustrating the reduction of sidetone through the bridge method: (T1) and (T2) terminals for the subscriber line, (SH) switch hook in position to receive a call, (R) ringer, (D) dial, (IC) impulse contact of the dial, (Rc) receiver, (Tr) transformer, (M) transmitter, (2) impedance of the balancing network, and (C1) and (C2) contacts of the switch hook

The design of the set’s housing depends on whether the central office providing service is manual or automatic. In a telephone set served by a manual office, a magneto is used to send calling signals to the office or directly to another telephone set; alternatively, calling signals can be sent to the office upon the lifting of the handset. In a set served by an automatic office, calling signals are sent by means of a key pulser or a dial. The telephone set is shifted from a state of readiness to receive ringing signals to a state wherein a conversation can be carried on, and vice versa, by means of the switch hook. The subscriber is alerted to an incoming call by the electric ringer or, more rarely, by a lamp.

The most important components of the handset are the receiver and the transmitter; for convenience, these components are combined in a single structural unit. Depending on the method of supplying power to the transmitter, telephone sets are classified as central-battery, in which the battery is usually installed at the central office, or local-battery, in which a galvanic cell is located either inside or nearby the set’s housing. A distinction is also made between anti-sidetone telephone sets and side-tone sets, now virtually obsolete (sidetone being the sound of the speaker’s own voice as heard in the receiver). Depending on the method of reducing effect, anti-sidetone sets are further subdivided into bridge and compensation types.

When a telephone set of the bridge type (Figure 1), is in the “talking” state, the transformer windings of the transmitter circuit, the balancing network, and the subscriber’s line form a bridge circuit with the transmitter connected across the diagonal; the sidetone is reduced by making the impedance of the balancing network equal to the line impedance (by fitting resistors and capacitors of the balancing network). Circuits of the compensation type differ from bridge circuits in having a connection between the receiver and the other circuits of the telephone set through a varistor.

Telephone sets are available in the form of table, wall, integrated (a combination of table and wall), and portable models.

The different types of telephone sets include pay stations; sets with a transistor amplifier in the transmitter and/or receiver circuits, used when the transmitting or receiving signal is below a certain level; loudspeaker telephone sets; telephone headsets, used in radiotelephone communications; and videotelephone sets.


Gubrenko, I. M., and E. V. Kuchumov. Telefonnye apparaty ATS. Moscow, 1968.
Gubrenko, I. M., and E. V. Kuchumov. Telefonnye apparaty, ispolzuemye v sel’skoisviazi. Moscow, 1969.


References in periodicals archive ?
Retailers can handle this by carrying brands which are reliable, by setting up service centers or seeing that service centers are set up, and handling consumer problems with telephone sets promptly and effectively.
Coverage includes automatic telephone exchange switching, cordless handsets, demodulators, digital line systems, entry phone systems, facsimile machines, modulators, relays, switching equipment, telegraphic equipment, telephone sets, teleprinters, and video phones.
Koncept is a leading designer and developer of patented VoIP technologies including VoIP telephone sets, gateways, softphones with a fully integrated softswitch, billing, and OSS platforms with worldwide call termination through its own Federal Communications Commission (FCC) 214 licensed carrier and other carrier agreements.
Main features: The orders to the market for the provision and delivery of telephone sets analogue (, digital, VOIP Softphone), telephone headsets, small equipment and spare parts (atria cords, batteries, tester .
The purpose of this Invitation to Bid (ITB) is to supply the Baldwin County Commission with Unify IP Telephone sets.
The CITELlink SIP gateway is a Handset Gateway designed to allow enterprise customers access to next generation features and functionality while leveraging their existing investment in traditional telephone sets and associated wiring infrastructure.
Limited Tenders are invited for Procurement Of Caller Id Cards Telephone Sets And 1+1 Type Telephone Sets
Sales and marketing of wireless communication devices, including mobile telephone sets
With Amedia's QoStream Premises Gateway, carriers can offer highly economical and feature rich Voice over IP (VoIP) services to their subscribers without any need for those subscribers to change their existing telephone sets.
Nimcat's nimX - embedded, P2P call processing software - takes the intelligence usually found at the PBX and distributes it to end-user telephone sets.
Nimcat has overcome SMEs' problems by developing smart, VoIP-ready call processing software that relies upon intelligent, plug-and-play telephone sets to establish (P2P) connections.