Psion Epoc 5mx

The best miniature business PDA of the 20th Century

The 1999 update to the original Psion 5.

Twice the memory and twice the speed of the original Psion 5. Case is more gray, and no longer peels. There are also a number of Epoc software changes, as it moves to Epoc Release 5. Wallpaper can be used on screen. You can select multiple files to send via IrDA.


32 bit 36MHz ARM 7100 CPU
Touch sensitive 640 x 240 slightly improved backlit display with 16 grey scale. 133mmx50mm (5.25"x2.0") 100 characters by 26 lines maximum. Multi level zoom of character size.
Weight, Size, Power
360 grams, or 13 ounces. 170x90x23mm (6.7"x3.5"x0.9"). Up to 35 hour battery life from two AA alkaline cells, although if you use the backlight about 10 hours is more likely. 3V CR2032 lithium backup. Optional 6V external power supply.
Larger ROM (10MB - build 250, and 16MB - build 260 has multi-language ROM with several language source files). 16MB RAM, same as Revo Plus (twice Revo and Series 5 Classic). Compact Flash slot for memory expansion.
Vertical expanding keyboard, 9 application buttons, 5 command buttons. Unfolds from case, large vertical travel (for a palmtop).
Includes external buttons for record, stop/play, rewind, silence alarm sounds. Can be used while computer is closed.
115kbps RS232 serial port (Honda connector). 115kbps IrDA infrared port direct to printer, and to other computers after software updates. IrDA supports selecting multiple files.


Word Processor
Multiple fonts, bold, italics, bullets, borders, etc. Paragraph styles. Embed sketches, spreadsheets, sounds. Spelling checker. Zoom display. WYSIWYG. Password protect files. Outliner added to 5mx.
Text formatting similar to word processor, auto-sum, 100 functions, zoom, seven chart types including 3D. Up to 16 row by 17 columns visible. Sorting function added to 5mx.
Unlike Windows CE 1, you get printing support for a selection of printers, via cable or IrDA infrared, or via Windows using True Type fonts. Print preview multiple pages at a time. Printing not as satisfactory as in 5.
Drawing tools, using stylus provided with Psion. Clipart library, zoom, resize. This is a paint (pixel oriented) drawing package, not a vector oriented package.
Time management, with day, week, month and year views and alarms. Attach notes, sketches, sound. To-do items. Very powerful. Busy view of month added to 5mx.
Card view of records, list view of multiple records, embed sketches, sound or objects, sort.
Record voice and sounds, even with case closed. Store 2 minutes per megabyte with compression, up to 4 minutes with ADPCM.
Four function with "tape". Scientific, multi function, with ten memories. Use touch screen if desired.
Select sounds or recordings for alarms, local times in 700 locations, add your own. Flexible multiple alarms. Daylight saving.
PC Docking
Serial cable with Honda connector. Windows 95/NT PsiWin2 conversion program included, Psion appears as an icon in Windows.
Programming language
OPL built in.
VT100 and TTY terminal emulation, ASCII, Xmodem, Ymodem protocols. Free Message Suite software provides fax, limited web browser, email.
Jotter (added to 5mx)
Quick data derived jotter application for ad hoc notes, embed sketches, etc.
Contacts (added to 5mx)
vCard compatible contacts list, works with email.
Email (added to 5mx)
Mime and uuencode, SMS and fax, works with Contacts application.
Web (added to 5mx)
Web browser, supplied on CD Rom, now handles frames, and can have Java 1.1.4 support.

Psion 5mx Pro

This German only model was originally a 16 MB machine, with the bootloader software loaded into flash memory. The operating system loaded into RAM. Psion used them for testing various country releases, as they didn't have to reflash various machines to test new ROM versions, according to Clive Evans. You probably can't find any OS images except for the German version (sys$rom.bin on some PsiWin CDs). The model as sold had 32 MB, at least 12 MB of which was occupied by Epoc and the applications.

The 5mx Pro was originally going to be released in all markets, but Product Marketing decided fairly late in the game that the demand for it wasn't sufficient to justify the extra cost (5mx Pros are more expensive and they believed, rightly or wrongly, that the higher price would prevent people from buying them).

In December 2001 a similar model to the Pro was reported with a Japanese system. In 2003, some Psion 5mxPro models with an UK OS were sold.

Multilingual ROM

Some models of the Psion 5mx (build 260) have 16 MB of ROM instead of 12 MB (built 250). This contains resource files for several language variants. Clive Evans says the language variant is controlled by a setting in the E squared chip. Psion Service Centres have ways of rewriting the E squared chip, but as you can do nasty things to the Psion, the software has not been generally released.

Software Updates from Psion

dBase III, IV, 5 Converter upgrade, for files after 31 Dec 1999, with PsiWin 2.1 to 2.3.1 only. 132KB

Email Synchronisation update 1.1 for PsiWin 2.3 and 2.31 (1.18MB).

InSync Pro upgrade for PsiWin 2.2 for Lotus Notes 5 (1.98MB).

InSync Pro(e) upgrade for PsiWin 2.3 for Lotus Notes 5, Lotus Email and Contact Manager (1.98MB)

Lotus Organiser 5.0 and 6.0 plugin for PsiWin 2.3 and above (1.34MB).

MacConnect 1.1.4 upgrade for Macintosh OS 8.5 (194KB)

MacConnect 1.1.4 upgrade for Macintosh OS 9.0 (132KB), also 1.1 upgrade (407KB)

Mobile Connectivity Update 1.1 (604KB) connectivity with some data enabled mobile phones (Siemens S25, Sagem M8300, Bosch GSM908, Motorola Timeport L7089). (For 5mx and Pro only, not 5, Revo or 7)

PsiWin 2.3.3 PC connectivity and synchronisation for all 32 bit Windows (25MB). Also available on CD.

PsiWin 2.3.1 PC connectivity and synchronisation, provided for users of InSync Pro(e). All others use latest version. (25MB).

Synchronisation upgrade for PsiWin (helps with duplicate entries in Contact) (132KB)

Various Topics

The 5mx was designed by Psion, but production was outsourced (sometime in 1999 I believe) and it was built for Psion by Flextronics.

The Machine Unique ID that you can view from the System screen is not the serial number. The serial number is usually under the battery door. The unique ID is sometimes used by software to lock a program to a particular Psion. The serial number is what you need for warranty repairs and so on.

A more robust display cable has been designed by a German company. Those into delicate surface mount soldering can find it here or also here

This site will look much better in a browser that supports W3C web standards but it is accessible to any browser or internet device, including Psion Web and similar PDA or limited browsers. Netscape 4.x users - turn Style Sheets off. Your style sheet support is too broken to use (sorry). -> epoc -> epoc hardware -> psion5mx

Contact Webmaster PO Box 640, Airlie Beach, Qld 4802 Australia