Psion Series 3 and 5
Psion introduced its first hardware product, the Organizer, in 1984 and followed up this calculator-style electronic organizer with the superior Organizer II, II XP, II LZ and II LZ 64 over the coming years.
In 1991, Psion introduced the Series 3, its third-generation organizer, this time in a clamshell palmtop form-factor that also marked a transition from the Organizer’s ABCDEF keypad to a QWERTY keyboard, and incorporated a much larger LCD display.
The Psion 3a
Psion subsequently introduced the Series 3a, in 1993, with an even larger screen. This was soon followed three years later by the 3c and, in 1998, the 3mx, the final Series 3 device.
The first Series 5 was launched in 1997. It was a larger palmtop with a bigger, more computer-style keyboard, a stylus for its touch-sensitive screen, and, in a significant upgrade, a jump from the 3’s 16-bit OS, SIBO, to a 32-bit alternative, EPOC.
The Psion 5mx
The last Series 5, the 5mx, was released in 1999. It was faster than the 5 and included more memory. Psion also offered the Series 5mx Pro, which copied the ROM to RAM on boot, allowing it to be upgraded. The mx Pro was not common.
The Psion 5mx
The Series 3 was superseded in 1999 by the Revo, launched alongside the Series 5. It was accompanied by the Revo Plus, a model with more memory.
Psion licensed its palmtop designs to a small number of third parties. Acorn rebadged the Series 3 and 3a as, respectively, the Pocket Book and Pocket Book II. Both features the Acorn logo in place of Psion’s and green colouring rather than Psion’s yellow.
Siemens offered its own version of the Series 5mx, called the MC218.
Psion Guides