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Terrestial Trunked Radio

TErrestial Trunked RAdio (TETRA) is a specialist cell phone and walkie talkie standard used by police, ambulance and military. Its main advantage over technologies such as GSM are:

Its main disadvantages are: TETRA uses Time Division Multiple Access (TDMA) with four user channels on one radio carrier and 25 kHz spacing between carriers. Both point-to-point and point-to-multipoint transfer can be used. Mobile Stations (MS) can communicate Direct Mode or using infrastructure made of TETRA Base Stations (TBS).

All traffic is normally encrypted. TETRA provides both transfer encryption and end-to-end encryption.

In Europe, TETRA uses frequencies:

TETRA is an ETSI standard, first version published 1995.

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