Inmarsat C

Inmarsat-C devices can be setup by configuring them for automatic polling and having the information routed to InmarsatC@{ShortDomain}.



An Inmarsat C terminal is activated by programming a DNID and member number (1-255) onto the terminal which allows the terminal to communicate with the Inmarsat ground station and pass traffic on the specific DNID. This can be programmed over the air by performing a “DNID Download” command which pushes a DNID and member number to the remote terminal. Once the DNID download is successful in any ocean region, the terminal can then pass traffic in any ocean region.


Once a terminal has been successfully activated with a DNID and member number, you can poll the terminal in all ocean regions, or a specific ocean region, and request an immediate position which will be returned in another message. A successful poll request means the remote terminal has received the poll request and is processing a response. When the position has been acquired and ready to transmit, it will transmit the current location. Polling does consume more airtime as there is a charge for the poll message, and a charge for the position response.

Scheduled Reports

Once a terminal has been successfully activated with a DNID and member number, it can also be programmed to send a position on an automatic interval. A single command is sent to set a schedule on the terminal, and the terminal will automatically acquire and send position reports. This does consume less airtime than polling for positions as there is only a position response, and not a poll command for every position.