The Inmarsat Development and Authorization Test Set (DATS) consists of a Protocol Tester (PTT) and a mini-M/M4 Physical Layer Tester (MPLT), which in turn consists of an RF Unit (RFU), an IF Unit (IFU) and a Channel Unit (CU). It is used for development and type approval of Land Earth Stations (LESs) and Mobile Earth Stations (MESs) for the Inmarsat mini-M, M4, M4-Aero and F systems.
The figure shows the most flexible configuration of the MPLT and its connections within the DATS. In installations where only one type of equipment will be tested, reduced MPLT configurations can be used. For LES-only testing the RFU can be omitted while for MES-only testing the IFU can be omitted. Any combination of external SCPC interfaces (Voice codec, FIU/MIU or HSD) can be ordered.