science

Push-button telephone

Push-button telephone 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 Push-button telephone rather than just read about it. In short: A push-button telephone is a telephone that has buttons or keys for dialing a telephone number, in contrast to a rotary dial used in earlier telephones. Western Electric experimented as early as 1941 with methods of using mechanically activated reeds to produce two tones for each of the ten digits and by the late 1940s such technology was field-tested in a No. 5 Crossbar switching system in Pennsylvania.

Key takeaways

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

Reference excerpt

A push-button telephone is a telephone that has buttons or keys for dialing a telephone number, in contrast to a rotary dial used in earlier telephones. Western Electric experimented as early as 1941 with methods of using mechanically activated reeds to produce two tones for each of the ten digits and by the late 1940s such technology was field-tested in a No. 5 Crossbar switching system in Pennsylvania. The technology at that time proved unreliable and it was not until after the invention of the transistor that push-button technology became practical. The Bell System selected Findlay, Ohio as the first city in the U.S. for marketing tests of touch-tone service and Ohio Bell began installing push-button telephones in Findlay homes starting on 1 November 1960. The next market was in Greensburg, Pennsylvania, starting on 1 February 1961. On 18 November 1963, after approximately three years of customer feedback, the Bell System officially introduced dual-tone multi-frequency (DTMF) technology in Carnegie, Pennsylvania and increased its use in Greensburg, under its registered trademark Touch-Tone. Over the next few decades touch-tone service replaced traditional pulse dialing technology and it eventually became a world-wide standard for telecommunication signaling. Although DTMF signaling was the driving technology implemented in push-button telephones, some telephone manufacturers used push-button keypads to generate pulse dial signaling. Before the introduction of touch-tone telephone sets, the Bell System sometimes used the term push-button telephone to refer to key system telephones, which were rotary dial telephones that also had a set of push-buttons to select one of multiple telephone circuits, or to activate other features. Digital push-button telephones were introduced with the adoption of metal–oxide–semiconductor (MOS) integrated circuit (IC) technology in the early 1970s, with features such as the storage of phone numbers (like in a telephone directory) on MOS memory chips for speed dialing.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Push-button telephone

Start with the simplest possible case. Write down what Push-button telephone 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 Push-button telephone 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 Push-button telephone 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 Push-button telephone

In research: Push-button telephone 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 Push-button telephone 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: Push-button telephone is common in secondary-school and first-year university syllabi. It links to neighbouring topics Telecommunications-related introductions in 1963, Telephony equipment, so understanding it makes those chapters shorter.
In everyday life: Look for Push-button telephone 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 Push-button telephone in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Push-button telephone 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 Push-button telephone out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Push-button telephone in simple terms?

Why does Push-button telephone 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 Push-button telephone?

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 Push-button telephone.