Editing Psion Series 3mx (section)

== What changed from the 3c ==

{| class="wikitable styled-table" style="width:70%; text-align:left;"
|+'''Series 3c → Series 3mx'''<ref name="wp3" /><ref name="spec">[https://www.psion.netogram.com/psionspecifications.html "Psion 3mx, Psion 5, Psion 5mx, Psion Revo and Psion Revo Plus specifications"], netogram.com. Source for the 3mx ROM and RAM sizes, external power rating, backup cell, keyboard layout, CODEC sample rate and DTMF auto-dialling.</ref>
! Change !! Detail
|-
| '''Processor''' || '''NEC V30MX''' at '''27.684 MHz''', replacing the V30H at 7.68 MHz
|-
| '''ROM''' || 2 MB, up from 1 MB
|-
| '''Serial''' || '''Fast serial port, up to 115 kbit/s''' — roughly double the 3c
|-
| '''Backlight''' || '''All''' 3mx models are backlit, where the 3c's was a late and largely US option
|-
| '''Backup cell''' || '''CR2025''', not the CR1620 used by the Series 3, 3a and 3c
|-
| '''Finish''' || Matte '''silver metallic''' paint, against the 3c's dark grey
|-
| '''External power''' || 9 V, 250 mA
|-
| '''SSD door sensing''' || '''A pair of angled microswitches''', replacing the 3c's PCB tracks and door-hinge contact
|}

'''The backup cell change is the one to remember.''' A 3mx takes a '''CR2025''' and the earlier machines take a '''CR1620''' — different diameter and different thickness. Fitting the wrong one is a common and avoidable mistake.<ref name="wp3" />

Everything else carries over: the 480 × 160 screen, the 58-key keyboard with 9 touch-sensitive application keys, two internal SSD slots, an infrared port, 2 × AA cells and the same 165 × 85 × 22 mm case at 275 g.<ref name="spec" />