TETRA Direct Mode solution is offered as encrypted or non- encrypted for users;
-Demanding usage in a limited area
-Instead of requirements of wide coverage area, central management needs to communicate over a single base station,
-Have high number of user groups and the calling frequency,
-It is necessary to use TDMA (Time-Division Multiple Access) because it is important to efficiently allocate the frequency in the region where the communication occurs,
-Generally, who are in need of communication in city centers
In TDMA technology, while a call is on the physical channel, another user may initiate a call and continue two different calls on the same physical channel while a physical channel determined in the FDMA technology (e.g., a channel with a bandwidth of 12.5 kHz) is available only by the caller initiating a call. When the number of time slots is increased, the number of calls that can be performed on the same physical channel increases. Since the TETRA communication protocol has 4 time slot TDMA structure, four different calls can be made in the same physical channel, thus ensuring frequency efficiency.
If the communication needs of users change and a more advanced solution is required:
-In addition to base stations installed for TETRA Direct Mode, the installation of different base stations,
-Establishing a system management centre,
-Connecting the installed base stations to each other and to the switching unit in the system management centre,
-Programming the radios according to the new architecture,
it is possible to switch to the TETRA Trunk Wide Area System configuration.