Users write their e-mail using standard clients, using any combination of character sets.
There are about a dozen systems available that route e-mail between the Internet and mobile users. Present gateways have many drawbacks like proprietary editors which only support 7-bit character sets and are limited to just one line of communication like Inmarsat services. Or obsolete communication standards like X400 with costly message overhead of large headers. Automated tasks like scheduled location reporting call for extra equipment and software. High costs currently hamper proper communications and in all but very few cases where standard e-mail programs can be utilized aboard today, a second set of satellite equipment is called for, because of the fact that mandatory equipment can never be disconnected.