The INMARSAT D Plus service was terminated as of Wednesday, December 31, 2014. Inmarsat C is recommended as one of the good options for the replacement of the service.
For the details, please visit below:
The INMARSAT D Plus equipment is a bi-directional packet communications system (up to 80-bit transmission and 256-bit receiving) that transmits using the stored packet exchange method, so it takes approximately 2 minutes for reception after transmission.
KDDI provides the INMARSAT D Plus service through the remote web site "K-SAP (KDDI Security Alert web Page)" that we use to run INMARSAT D Plus equipments.
In addition, we also sell ship security systems that use INMARSAT D Plus terminals, which can use the KDDI INMARSAT D Plus services.