Nokia Communicator 9000
"The Communicator 9000 combines a GSM phone with applications like fax, e-mail, short messaging and Internet access. It also includes the most useful organizer functions; a calendar, an address book and a calculator. All of this is available in a sophisticated, pocket-sized unit," Nokia said when the device was launched in 1996.
The device was a brick at 397 grams, but a phone that could be opened up to reveal a handheld computer was a big step.