OLT (

Norwegian Norwegian, Norwayan, or Norsk may refer to: *Something of, from, or related to Norway, a country in northwestern Europe *Norwegians, both a nation and an ethnic group native to Norway *Demographics of Norway *The Norwegian language, including the ...

for ''Offentlig Landmobil Telefoni'', Public Land Mobile Telephony), was the first land mobile telephone network in Norway. It was established December 1, 1966, and continued until it was obsoleted by

NMT NMT may refer to: Science and technology * Nordic Mobile Telephone, an analogue mobile phone system * Neurologic Music Therapy * Neural machine translation * Network management protocols, in the CANopen#Network management (NMT) protocols, CANopen ...

in 1990. In 1981, there were 30,000 mobile subscribers, which at the time made this network the largest in the world. The network operated in the 160 MHz

VHF Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VHF ...

band, using

frequency modulation Frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. The technology is used in telecommunications, radio broadcasting, signal processing, and Run-length limited#FM: .280. ...

(FM) on 160-162 MHz for the mobile unit, and 168-170 MHz for the base station. Most mobile sets were semi-duplex, but some of the more expensive units were

full duplex A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow ...

. Each subscriber was assigned a five digit phone number. In 1976, the OLT system was extended to include

UHF Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter (on ...

bands, incorporating

MTD MTD may refer to: Medicine * Maximum tolerated dose, in drug development * Muscle tension dysphonia, hyperfunctional musculature causing a hoarse voice Organizations * Makkal Tamil Desam Katchi (People's Tamil Land Party), a political party i ...

, and allowing international roaming within

Scandinavia Scandinavia; Sámi languages: /. ( ) is a subregion#Europe, subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, ...

n countries.

External links

Norwegian mobile phone history
from Norsk Telemuseum (Norwegian) {{Mobile telecommunications standards Mobile radio telephone systems