I have s3b and s3c main units.
type Handheld computer
country UK
year 1993
os epoc
cpu 16-bit NEC V30H
speed 7.68 MHz
ram 256 KB (s3b) / 2MB (s3c)
rom 1 MB
graphic 480×160
colors 2
sound Membrane speaker
power two AA battery
ports serial, ssd slot (2)
The Psion Series 3 — Britain’s Finest Handheld Computer
The Psion Series 3, launched in 1991 and refined through the 3a, 3b, and 3c variants, was Britain’s most celebrated handheld computer — a clamshell device with a superb keyboard, a suite of built-in applications (word processor, spreadsheet, database, agenda, and more), and battery life measured in weeks rather than hours. Running the EPOC16 operating system on a 7.68 MHz V30 processor, the Series 3 offered genuine productivity capability that competing PDAs could not match. The 3a’s improved memory and the 3c’s flash storage and serial port made each revision more capable. Psion’s Series 3 established the template for the clamshell PDA and directly influenced the EPOC/Symbian platform that would power Nokia smartphones a decade later.