mathematics

Telephone numbers in Germany

Telephone numbers in Germany is a mathematics 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 Telephone numbers in Germany rather than just read about it. In short: The regulation of telephone numbers in Germany is the responsibility of the Federal Network Agency (German: Bundesnetzagentur, BNetzA) of the German government. The agency has a mandate to telecommunications in Germany and other infrastructure systems.

Key takeaways

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

Reference excerpt

The regulation of telephone numbers in Germany is the responsibility of the Federal Network Agency (German: Bundesnetzagentur, BNetzA) of the German government. The agency has a mandate to telecommunications in Germany and other infrastructure systems.

Overview Germany has an open telephone numbering plan with variable sizes of area codes and subscriber telephone numbers. Before 2010, area codes and subscriber telephone numbers had no fixed size, meaning that some subscriber numbers may be as short as two digits. As a result, dialing sequences are generally of a variable length, except for some non-geographic area codes for which subscriber numbers use a fixed-length format. It is not possible to determine unambiguously the end of a phone number from a prefix or the digits already dialed. This feature allows the extension of the numbering plan without revoking or changing existing numbers. Mobile telephones are assigned to non-geographic codes, making them readily recognizable. A new numbering plan was introduced on 3 May 2010. Since then newly assigned landline telephone numbers have a standard size of eleven digits, including the area code. Area codes remained unchanged, variable in length. Exceptions to the eleven-digit rule are the cities of Berlin, Frankfurt, Hamburg, and Munich, which are the only cities with two-digit area codes and have ten-digit numbers to avoid exceeding the maximum length of eight digits for a subscriber number. The German telephone network uses 5,200 geographical area codes, varying from two to five digits (not including the trunk code 0), with five-digit area codes being assigned only in the New States, starting with the digit 3. In general, geographic area codes start with digits 2 to 9, whereas other non-geographic area codes (including those for cell phones) are assigned to 1 and network services to 11.

Geographic numbering

Geographic area codes consist of two to five digits. The maximum size of the national telephone number is eleven digits. Telephone numbers with geographic area codes are assigned to carriers in blocks. Subscriber numbers do not start with 0 or 11 and can be dialled without the area code from landlines within the same geographic area code. Originally, the first digits following the area code indicated a smaller service area or the type of the subscriber line (analogue or ISDN). This is no longer true as subscribers can keep their numbers when moving within an area code or when switching from analogue to ISDN. Furthermore, new carriers assign numbers from different blocks.

(xx) xxxx-xxxx This is the format used for the four largest geographic areas in Germany: Berlin (30), Hamburg (40), Frankfurt (69) and Munich (89). Newly assigned numbers have a length of eight digits for the local subscriber number, yielding a total length of ten digits (not including the 0 trunk code). This is shorter than the maximum of eleven digits in other areas to avoid exceeding eight digits. Numbers assigned in the past, which are generally grandfathered, may be as short as five digits. (xxx) xxxx-xxxx In area codes of three digits, newly assigned numbers (for all locations from May 2010; earlier in some cities, e.g. Cologne in February 2007) also have eight digits, yielding a total of eleven digits. Grandfathered numbers may be as short as four digits (seven total). (xxxx) xxx-xxxx In area codes with four digits, newly assigned numbers (for all locations from May 2010, earlier in some cities, e.g. Heidelberg in May 2003) have seven digits, also yielding a total of eleven digits. Grandfathered numbers may be as short as three digits (seven total) in very rural areas. (3xxxx) xx-xxxx Some smaller areas in the former East Germany have five-digit area codes, all of which start with 3. Newly assigned numbers (for all locations from May 2010, earlier in some locations) have six digits, also yielding a total number length of eleven digits.

Non-geographic numbering

Non-geographic numbers were originally assigned the prefix 1. However, some of these services have been moved to other area codes.

10xy, 100yy These numbers can be dialled before the telephone number to select a carrier. 11… Area codes starting with 11 overlap the prefix for network services. In general, these numbers cannot be dialled from abroad, with the exception being 116xxx for harmonised services of social value. 12xx-xxxxxxx… The prefix 012 has been assigned as a testbed for innovative services, such as VoIP or unified messaging, for which no other area codes were available. Allocations were only valid for a maximum of five years, after which new numbers would have to be assigned. Recent requests for registrations have been declined and referred to the premium-rate services under 900. When the last remaining allocation expires in 2011, the prefix is planned to be returned to the reserved range. 137-xxx xxxxxxx, (138-1xxx…) The area code 137 is assigned for services that may result in a high number of connections in a fairly short period of time, e.g. votes or competitions initiated from TV or radio shows. The first digit indicates the rate for a call, the second digit indicates the maximum number of calls that can be handled per time period. There are also sixteen grandfathered numbers in the range 138-1, which were originally allocated by Deutsche Bundespost. 15xx-xxxxxxx, 16x-xxxxxxx, 17x-xxxxxxx Mobile numbers are assigned non-geographic area codes starting with 15, 16 and 17 and have a length of three or four digits without the trunk prefix. The numbers have a total length of ten or eleven digits without the trunk prefix: numbers starting with 17 or 16 are ten digits long, except 176 and 1609, which have eleven digits like the numbers starting with 15. Network operators issue area codes as listed in the following table.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Telephone numbers in Germany

Start with the simplest possible case. Write down what Telephone numbers in Germany claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, 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 Telephone numbers in Germany 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 Telephone numbers in Germany 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 Telephone numbers in Germany

In research: Telephone numbers in Germany appears in mathematics 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 Telephone numbers in Germany 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: Telephone numbers in Germany is common in secondary-school and first-year university syllabi. It links to neighbouring topics Germany communications-related lists, Telecommunications in Germany, Telephone numbers by country, so understanding it makes those chapters shorter.
In everyday life: Look for Telephone numbers in Germany 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Telephone numbers in Germany” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Telephone numbers in Germany in 20 minutes

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

Frequently asked questions

What is Telephone numbers in Germany in simple terms?

Why does Telephone numbers in Germany matter?

Because it connects several mathematics 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 Telephone numbers in Germany?

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 Telephone numbers in Germany.