In addition to placing and receiving cellular calls, the touch screen-equipped Simon could send and receive faxes and emails.
It included an address book, calendar, appointment scheduler, calculator, world time clock and notepad, as well as other visionary mobile applications such as maps, stock reports and news.
The first caller ID equipment was installed at Peoples' Telephone Company in Leesburg, Alabama and was demonstrated to several telephone companies.
Apps can receive bug fixes and gain additional functionality through software updates; similarly, operating systems￼￼ are able to update.
The trend at the time, however, that manufacturers competed on in both mobile phones and PDAs was to make devices smaller and slimmer.
The bulk of these smartphones combined with their high cost and expensive data plans, plus other drawbacks such as expansion limitations and decreased battery life compared to separate standalone devices, generally limited their popularity to "early adopters" and business users who needed portable connectivity.
It was also 100% DOS 5.0 compatible, allowing it to run thousands of existing software titles, including early versions of Windows.
In August 1996, Nokia released the Nokia 9000 Communicator, a digital cellular PDA based on the Nokia 2110 with an integrated system based on the PEN/GEOS 3.0 operating system from Geoworks.