The Simon combined a cellular phone with a PDAPersonal digital assistant — a pocket device for calendar, contacts, and email before smartphones. — users tapped a stylus on a monochrome LCD for fax, email, and address book apps. It was bulky and expensive, but proved the smartphone concept before Palm and BlackBerry refined mobile messaging. Mobile developers today trace a lineage through these early converged devices.

The IBMInternational Business Machines — a major computer and enterprise technology company since the early 20th century. Simon was the first phone sold with PDAPersonal digital assistant — a pocket device for calendar, contacts, and email before smartphones. features and downloadable applications.

It demonstrated demand for pocket computers that also made calls — a decade before smartphones went mainstream.