scope:

The present document defines the general aspects of interworking at the Inter-System Interface (ISI) for Terrestrial Trunked Radio (TETRA) system supporting Voice plus Data (V+D). Those specify the general concepts which are the basis of the ISI operation between TETRA systems. It introduces the Additional Network Features (ANFs) used at the ISI, and specifies:

• the general protocol mechanism upon which the definition of each ANF is based; and

• the security related functions over the ISI.

The specification of the general transport layer independent protocol mechanism applies to any TETRA Switching and Management Infrastructure (SwMI) which supports the ISI. The security requirements for the ISI only apply to SwMIs which support authentication or end-to-end encryption over the ISI.

Besides the ISI general design, the present sub-part, interworking at the Inter-System Interface comprises the following other sub-parts:

• General design, PSS1 over E.1 [3];

• General design, SIP/IP [4];

• Transport layer independent Additional Network Feature Individual Call (ANF-ISIIC) [5];

• Transport layer independent Additional Network Feature Group Call (ANF-ISIGC) [6];

• Transport layer independent Additional Network Feature Short Data Service (ANF-ISISDS) [7];

• Transport layer independent Additional Network Feature, Mobility Management (ANF-ISIMM) [8]; and

• Generic Speech Format Implementation [9].