Inmarsat-C is a low-speed, store and forward two-way messaging service operating over the Inmarsat satellite constellation. Inmarsat-C has been in operation since the early 1980s. Inmarsat-C Mobile Earth Stations (MESs) are developed and sold by a number of manufacturers for use on the network.
The Inmarsat-C Physical Layer Tester (CPLT) supports testing of the physical layer performance and protocol implementations of Inmarsat-C Mobile Earth Stations (MESs) and Land Earth Stations (LESs). The CPLT provides a Test Sequencer user interface compatible with that used with legacy Inmarsat-C test equipment. This facility allows users to execute existing type approval RTP scripts, while the channel simulator and signal allow verification of physical layer performance.