OLT was the first land mobile telephone network in Norway. It was established December 1, 1966, and continued until it was obsoleted by NMT

Nordic Mobile Telephone

NMT is the first fully automatic cellular phone system...

 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 band, using frequency modulation

Frequency modulation

In telecommunications and signal processing, frequency modulation conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant...

 (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. Each subscriber was assigned a five digit phone number.

In 1976, the OLT system was extended to include UHF bands, incorporating MTD

MTD (mobile network)

MTD was a manual mobile phone system for the 450 MHz frequency band. It was introduced in 1971 in Sweden, and lasted until 1987, when it was made obsolete by the NMT automatic service...

, and allowing international roaming within Scandinavia

Scandinavia

Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...

n countries.

External links

• Norwegian mobile phone history from Norsk Telemuseum (Norwegian)