Terrestrial Trunked Radio (TETRA) - Conformance testing specification - Part 4: Protocol testing specification for Direct Mode Operation (DMO); Sub-part 4-4: Test Suite Structure and Test Purposes (TSS&TP) for Direct Mode Repeater (DM-REP) type 1 (Endorsement of the English version EN 300394-4-4 V 1.1.1 (2001-01) as German standard)