ArticleslgStudy

biology

Nordic Mobile Telephone

Nordic Mobile Telephone is a biology 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 Nordic Mobile Telephone rather than just read about it. In short: NMT (Nordic Mobile Telephony) is an automatic cellular phone system specified by Nordic telecommunications administrations (PTTs) and opened for service on 1 October 1981. NMT is based on analogue technology (first generation or 1G) and two variants exist: NMT-450 and NMT-900.

Nordic Mobile Telephone — main illustration
Nordic Mobile Telephone — illustration

Key takeaways

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

Reference excerpt

NMT (Nordic Mobile Telephony) is an automatic cellular phone system specified by Nordic telecommunications administrations (PTTs) and opened for service on 1 October 1981. NMT is based on analogue technology (first generation or 1G) and two variants exist: NMT-450 and NMT-900. The numbers indicate the frequency bands used. NMT-900 was introduced in 1986 and carries more channels than the older NMT-450 network. The NMT specifications were free and open, allowing many companies to produce NMT hardware and pushing prices down. The success of NMT was important to Nokia (then Mobira) and Ericsson. The first Danish implementers were Storno (then owned by General Electric, later taken over by Motorola) and AP (later taken over by Philips). Initial NMT phones were designed to mount in the trunk of a car, with a keyboard/display unit at the driver's seat. "Portable" versions existed, though they were still bulky, and with battery life a big problem. Later models, such as Benefon's, were as small as 100 mm (3.9 inches) and weighed only about 100 grams.

History NMT stands for Nordisk MobilTelefoni or Nordiska MobilTelefoni-gruppen.

The NMT network was opened in Sweden and Norway in 1981, and in Denmark and Finland in 1982. It was a response to the increasing congestion and heavy requirements of the manual mobile phone networks: ARP (150 MHz) in Finland, MTD (450 MHz) in Sweden and Denmark, and OLT in Norway. Iceland joined in 1986. However, Ericsson introduced the first commercial service in Saudi Arabia on 1 September 1981 to 1,200 users, as a pilot test project, one month before they did the same in Sweden. By 1985 the network had grown to 110,000 subscribers in Scandinavia and Finland, 63,300 in Norway alone, which made it the world's largest mobile network at the time. The NMT network has mainly been used in the Nordic countries, Baltic countries, Switzerland, France, Netherlands, Hungary, Poland, Bulgaria, Romania, Czech Republic, Slovakia, Slovenia, Serbia, Turkey, Croatia, Bosnia, Russia, Ukraine, Belarus and in Asia. The introduction of digital mobile networks such as GSM has reduced the popularity of NMT and the Nordic countries have suspended their NMT networks. In Estonia the NMT network was shut down in December 2000. In Finland TeliaSonera's NMT network was suspended on 31 December 2002. Norway's last NMT network was suspended on 31 December 2004. Sweden's TeliaSonera NMT network was suspended on 31 December 2007. The NMT network (450 MHz) however has one big advantage over GSM which is the range; this advantage is valuable in big but sparsely populated countries such as Iceland. In Iceland, the GSM network reaches 98% of the country's population but only a small proportion of its land area. The NMT system however reaches most of the country and a lot of the surrounding waters, thus the network was popular with fishermen and those traveling in the vast empty mainland. In Iceland the NMT service was stopped on 1 September 2010, when Síminn closed down its NMT network.

In Denmark, Norway and Sweden the NMT-450 frequencies have been auctioned off to Swedish Nordisk Mobiltelefon which later became Ice.net and renamed to Net 1 that built a digital network using CDMA 450. During 2015, the network has been migrated to 4G. France also developed an NMT network in 1988 (in parallel with Radiocom 2000) but with slight variations. As a result, it could not roam with other NMT networks around the world. In Russia Uralwestcom shut down their NMT network on 1 September 2006 and Sibirtelecom on 10 January 2008. Skylink, subsidiary company of Tele2 Russia operates NMT-450 network as of 2016 in Arkhangelsk Oblast and Perm Krai. These networks are used in sparsely populated areas with long distance. Although license for the provision of services was valid until 2021, the last NMT-450 network in Russia ceased operation on 30 May 2017, when the last functioning base station located in Kotlas, Arkhangelsk region was switched off.

Legacy and Influence NMT (Nordic Mobile Telephony) not only pioneered mobile communications across the Nordic region, but also laid the groundwork for modern mobile network technology worldwide. Its open standard allowed manufacturers to innovate rapidly, leading to a competitive market and accelerating mobile adoption across Europe and Asia. NMT’s success and design principles directly influenced the development of the GSM (Global System for Mobile Communications) standard, which would become the world’s most widely used mobile technology. The European telecommunications community applied lessons from NMT—such as open interfaces and scalable coverage—to the development of GSM, which debuted commercially in 1991 and expanded to cover hundreds of countries. According to technology analysts, the far-reaching coverage of NMT’s 450 MHz band set benchmarks for mobile reach in remote and rural areas, influencing not only GSM but also the later rollout of LTE and 5G networks.

Technology The cell sizes in an NMT network range from 2 km to 30 km. With smaller ranges the network can service more simultaneous callers; for example in a city the range can be kept short for better service. NMT used full duplex transmission, allowing for simultaneous receiving and transmission of voice. Car phone versions of NMT used transmission power of up to 15 watt (NMT-450) and 6 watt (NMT-900), handsets up to 1 watt. NMT had automatic switching (dialing) and handover of the call built into the standard from the beginning, which was not the case with most preceding car phone services, such as the Finnish ARP. Additionally, the NMT standard specified billing as well as national and international roaming.

Signaling NMT voice channel is transmitted with FM (Frequency Modulation) and NMT signaling transfer speeds vary between 600 and 1,200 bits per second, using FFSK (Fast Frequency Shift Keying) modulation. Signaling between the base station and the mobile station was implemented using the same RF channel that was used for audio, and using the 1,200 bit/s FFSK modem. This caused the periodic short noise bursts, e.g. during handover, that were uniquely characteristic to NMT sound.

… excerpt ends here. Continue reading the full article.

Illustrations

Nordic Mobile Telephone: The Mobira Cityman 150, Nokia's NMT-900 mobile phone from 1989 (left), compared to the dual-band GSM Nokia 1100 phone from 2003.[1]
The Mobira Cityman 150, Nokia's NMT-900 mobile phone from 1989 (left), compared to the dual-band GSM Nokia 1100 phone from 2003.[1]
Nordic Mobile Telephone: Storno 980, an analog cellular telephone for NMT 900 networks.
Storno 980, an analog cellular telephone for NMT 900 networks.
Nordic Mobile Telephone: An NMT phone from the early 1980s made by Norwegian-based Simonsen Radiofabrikk
An NMT phone from the early 1980s made by Norwegian-based Simonsen Radiofabrikk
Nordic Mobile Telephone: Ericsson Hotline NMT-900 phone from 1995
Ericsson Hotline NMT-900 phone from 1995

Worked examples

Example 1 — a first encounter with Nordic Mobile Telephone

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

In research
Nordic Mobile Telephone appears in biology 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 Nordic Mobile 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
Nordic Mobile Telephone is common in secondary-school and first-year university syllabi. It links to neighbouring topics First generation mobile telecommunications, Mobile radio telephone systems, Products introduced in 1981, so understanding it makes those chapters shorter.
In everyday life
Look for Nordic Mobile 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.
Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Nordic Mobile Telephone” →

Affiliate

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

How to study Nordic Mobile Telephone in 20 minutes

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

Frequently asked questions

What is Nordic Mobile Telephone in simple terms?

NMT (Nordic Mobile Telephony) is an automatic cellular phone system specified by Nordic telecommunications administrations (PTTs) and opened for service on 1 October 1981. NMT is based on analogue technology (first generation or 1G) and two variants exist: NMT-450 and NMT-900.

Why does Nordic Mobile Telephone matter?

Because it connects several biology 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 Nordic Mobile 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 Nordic Mobile Telephone.

Tags

  • First generation mobile telecommunications
  • Mobile radio telephone systems
  • Products introduced in 1981
  • Telecommunications-related introductions in 1981

Keep exploring