science

Intercept message

Intercept message 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 Intercept message rather than just read about it. In short: An intercept message is a telephone recording informing the caller that the call cannot be completed, for any of a number of reasons ranging from local congestion, to disconnection of the destination phone, number dial errors or network trouble along the route. Background Before automation, calls to a disconnected or non-working number would be diverted to an intercept operator.

Key takeaways

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

Reference excerpt

An intercept message is a telephone recording informing the caller that the call cannot be completed, for any of a number of reasons ranging from local congestion, to disconnection of the destination phone, number dial errors or network trouble along the route.

Background Before automation, calls to a disconnected or non-working number would be diverted to an intercept operator. The operator would ask what number the subscriber was attempting to call, determine the reason for the intercept and relay the information to the calling party. The first automatic intercept systems used rotating magnetic drums containing multiple recorded phrases, with a computer or mechanical control system playing phrases in the proper sequence. Initially, the caller was given the option to remain on the line for a live operator after the announcement was completed; this has since been removed. These messages are generally performed by female voices, although male voices are used as well. Jane Barbe, Pat Fleet, and Joyce Gordon are well known for being the voices behind many intercept messages originating in the United States. Many of these recordings end with the phrase "This is a recording" to let the callers know that they have not reached a live operator.

No Such Number In some cases, attempts to call a non-working number would give the "No Such Number" tone, also known as the "crybaby" tone. Bearing resemblance to a siren, it played continuously after an invalid digit was dialed, effectively stopping the call before it could be processed. This tone was introduced by Bell Systems in 1941, and was intended to sound distinct from other telephone signalling used at the time. According to a document from Bell Labs, customers would confuse previous tones intended for this purpose with others already in use, necessitating the need for a more distinctive tone.

Message wording The precise wording of intercept messages is left to the discretion of each local telephone company, except that most such messages nowadays start with one of several special information tones, standardized by Telcordia when it was still called Bellcore. In the 1970s, for example, New York Telephone used the following:

I'm sorry; the number you have reached is not in service, or temporarily disconnected. The number you have reached is not in service at this time. This is a recording. Bell of Pennsylvania used the following:

I'm sorry, the number you have reached is not in service. Please check the number in your directory and dial again ... the number you have reached is not in service ... if you remain on the line, an operator will answer ... thank you, this is a recording. In rural areas, the name of the town from which the exchange service is furnished was often included in the message; this was especially true if the telephone company providing the service was not part of the Bell System.

Generic message adopted By the 1980s, a standardized generic message was adopted, and is in use in a vast majority of localities in America today. It reads as follows: We're sorry; you have reached a number that has been disconnected or is no longer in service. If you feel you have reached this recording in error, please check the number and try your call again.

Customized message The option also exists to replace the generic message with a customized message, as applicable, such as in cases where a subscriber's telephone number has changed, usually due to relocation. This service is known in America as Number Referral Service, and in Britain as Ceased Number Intercept. An example of a Number Referral Service intercept message is:

The number you have reached, old number, has been changed. The new number is new number. Please make note of this change.

Message triggers

Cancelled service When a customer moves and cancels their telephone service, an intercept message is often used even if no new number has replaced the old one.

The number you have reached, old number, has been disconnected. No further information is available about old number. A similar intercept occurs if a number has recently been unlisted; no new number is provided:

The number you have reached, old number, has been changed to a non-published number. In the past, the call would be forwarded to an intercept operator after usually two readings of the message; today, however, this procedure is not observed, and on some systems a fast busy signal follows the second reading of the message instead. (A busy or an Off-Hook may be used depending on the provider.)

Incorrect number dialed A different intercept message is used when the caller has dialed a number the first three digits of which have not yet been assigned within that area code. This message, too, formerly varied by locality; the following was used in New York City in the 1960s:

If you are calling a number outside New York City, please dial the area code and the local number. If you are dialing a New York City number, please check the number and dial again. This is a recording. If you need assistance, please call your operator. The standard version of this message in use today is the following. This is used when the three-digit exchange does not exist in that area code.

We're sorry; we are unable to complete your call as dialed. Please check the number and dial again, or call your operator to help you. Most of these messages start with the phrase "Your call cannot be completed as dialed." Sometimes a message would say to first dial a 1 or a 0 (the toll prefix for a trunk call) plus the area code of the called number. A message may also be played when 0 or 1 followed by an area code is prepended unnecessarily on landline phone calls to local destinations. As of 2021, area code dialing is required in multi area code areas even for local calls, making the "not necessary to dial a 1 or 0" message no longer relevant for some areas.

Toll-free number calling area As the owner of a toll-free telephone number must pay to receive all long-distance calls (including misdialed calls), a toll-free subscriber may request that the responsible organization for a toll-free number (often but not always the inbound long-distance carrier) configure the number to only be reachable from specific area codes, from within one province or state or from specified cities. (The original Bell System InWATS used wide multiple-state or province "bands" as calling areas; modern systems route more finely.) An example of a message for this reason reads:

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Intercept message

Start with the simplest possible case. Write down what Intercept message 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 Intercept message 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 Intercept message 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 Intercept message

In research: Intercept message 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 Intercept message 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: Intercept message is common in secondary-school and first-year university syllabi. It links to neighbouring topics Audiovisual ephemera, Telephony, so understanding it makes those chapters shorter.
In everyday life: Look for Intercept message 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 Intercept message in 20 minutes

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

Frequently asked questions

What is Intercept message in simple terms?

Why does Intercept message 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 Intercept message?

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 Intercept message.