Xmail: Messages sent by xboat.
Xmail carries information only; material objects may not be sent. The message
is digitally coded; xmail costs Cr10 per 20 kilobits per parsec. The message
may be sent using a standard Anglic character
set (about Cr10 for a 500 word message) or a picture may be reproduced
in facsimile (Cr20 for a 200x 200 bit matrix). The message is printed out
at its destination and delivered by a world's local mail system. -ld