science

Speakerphone

Speakerphone is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Speakerphone rather than just read about it. In short: 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.

Key takeaways

Speakerphone belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Speakerphone to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Speakerphone from memory before moving on to harder problems.

Reference excerpt

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 other end of the telephone line, while the microphone captures all voices of those using the speakerphone. The term speakerphone is also sometimes used for loudspeaker, as in "put it on speakerphone". Many telephones have an integrated speakerphone function which can be activated by pushing a single button. This button transfers the sound input and output from the handset to the ambient microphone and loudspeaker. Devices designed specifically for speakerphone use often have multiple microphone inputs arranged radially around the device to maximize sound input, such as may occur around a conference table. The most sophisticated units allow the connection of additional satellite microphones that can be placed some distance from the main unit.

Types of speakerphones Speakerphones may be broadly divided into two classes of Duplex:

Half-duplex Full-duplex Half-duplex speakerphones allow sound to travel only in one direction at a time, either: 1) into the speakerphone from the telephone line and out of its internal speaker to its user, or 2) from its user, into the microphone, and out through the telephone line. While the users of the speakerphone are speaking, the phone only transmits sound to the telephone line; its internal speaker is cut off and no sound arriving from the telephone line can be heard by the user. While the user of the speakerphone is quiet, the speakerphone only receives sound from the telephone line and its internal speaker broadcasts that sound to its user. There is a very definite, noticeable switching action each time the phone "changes directions" and a cough or other transient noise in the room may interrupt incoming sound from the far end of the telephone connection. Full-duplex speakerphones are able to transmit and receive simultaneously and there is no discernible change of transmission direction. These phones are much more complicated and often employ sophisticated digital signal processing algorithms to sort out the incoming sound and the sound in the room for echo cancellation. Their cost is also higher than for a half-duplex speakerphone.

Speakerphone setup Many modern speakerphones must first be calibrated to the acoustic characteristics of the room in which they will be used. During this calibration phase, they may make a variety of noises including ascending tones or chiming sounds. This calibration may be automatic or manually invoked by the user, and it may need to be repeated if the speakerphone is relocated within the room. A failure to be properly calibrated can be indicated by the occurrence of echoing, ringing sounds, or feedback.

Handset vs. base speakerphone Many cordless telephones have a handset speakerphone as well as a base speakerphone. The handset speakerphone allows hands free conversations away from the base unit. The base speakerphone is located in the base unit. The user must be at the base unit, but still gets the added benefits of having hands free conversations. Most base speakerphones have a secondary keypad for dialing calls on the base unit.

Worked examples

Example 1 — a first encounter with Speakerphone

Start with the simplest possible case. Write down what Speakerphone claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Speakerphone before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Speakerphone ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Speakerphone

In research: Speakerphone appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Speakerphone in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Speakerphone is common in secondary-school and first-year university syllabi. It links to neighbouring topics Telephony equipment, so understanding it makes those chapters shorter.
In everyday life: Look for Speakerphone outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Speakerphone in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Speakerphone means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Speakerphone out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Speakerphone in simple terms?

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.

Why does Speakerphone matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Speakerphone?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Speakerphone.