The communications terminal device stores data about a kind of a network used by a user of the communications terminal device in relation to a user code. The communications terminal device also stores data about a kind of a network used by a recipient of electronic mail in relation to a recipient name....http://www.google.com.hk/patents/US6574670?utm_source=gb-gplus-share專利 US6574670 - Electronic mail-capable communications terminal device and electronic mail communications method
