The present document is written as a "Read-me-first" manual or "Getting started with TETRA DMO". It is not intended to be a guide to the TETRA DMO standard nor an authoritative interpretation of the standard. If any conflict is found between the present document and the corresponding clauses in the TETRA standard then the standard takes precedence.

The aims of the present document are:

• to provide the reader with sufficient knowledge to engage in qualified discussions with the equipment and service suppliers;
• to expose the reader to the specific language and technical terminology used in the standard;
• to enable the reader to understand the flexibility in system design, system network topography, system availability, various modes of operation and security features;
• in clause 10, sufficiently detailed design information is given to allow link budget calculations to be carried out and outline radio coverage planning to be performed. Some preliminary calculations are also given for co-existence between trunked and direct mode terminals and also for the number of direct mode talk groups (Nets) that can operate simultaneously at the same location.

The scope of the present document of the DMO Designers' Guide adds detailed consideration of repeaters and gateways to the detailed consideration of mobile station to mobile station direct mode operation which was covered in the first edition.

It should be understood that, as in all standardization activities, there is an inherent conflict between the users' wish to have as broad a standard as possible and at the same time wanting to have as much as possible of that broad standard available and implemented right from the beginning of service. Potential equipment purchasers, network operators and service users should make sure they influence the suppliers to have their required functionality available when they need it.

Equipment manufacturers will use the broad flexibility provided within the standard to develop and implement equipment in various ways, and still be conforming to the standard. This broad availability of equipment, each optimized around certain features and functionalities, needs to be carefully analysed by network operators and system users to find the supplier with equipment suited best for their needs.