Also known as: TETRA, Terrestrial Trunked Radio
TETRA (Terrestrial Trunked Radio) is an ETSI digital trunked-radio standard built for public-safety and professional users, especially in Europe and much of the world outside North America. It uses four-slot TDMA and π/4-DQPSK (phase-shift keying).1
Overview
TETRA is a complete system standard — not just an air interface — with rich features: group and individual calls, direct mode, packet data, and strong security. Four timeslots per 25 kHz carrier give high capacity.
Technical characteristics
| Property | Value |
|---|---|
| Access | TDMA, 4 slots |
| Channel | 25 kHz |
| Modulation | π/4-DQPSK (18 kbps gross) |
| Vocoder | ACELP |
History
Standardised by ETSI from the mid-1990s; adopted broadly by European emergency services, transport, and military/government users.1
Deployment
National public-safety networks across Europe, the Middle East, Asia, and elsewhere, plus transport and utilities. Rare in North America, where P25 dominates public safety.
Decoding it with GopherTrunk
TETRA uses a distinct modulation and vocoder; consult the Status page for GopherTrunk’s current TETRA coverage.
Sources
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Terrestrial Trunked Radio — Wikipedia, for the ETSI TETRA standard, its four-slot TDMA air interface, π/4-DQPSK modulation, and the ACELP vocoder. ↩ ↩2