Psion Series 3a data transfer over serial interface to modern Linux

Psion Series 3a

Transferring data from and to the Psion Series 3a digital assistant is surprisingly easy, still. This is thanks to the plptools, that are still packaged for Ubuntu LTS and Debian.


  • Psion Series 3a
  • Psion Series 3 Link (RS232)
  • USB to D-sub serial adapter cable
  • Null modem adaptor or cable – only needed if the D-sub of the USB adaptor isn’t male
  • A Linux system with USB interface and the plptools package installed


  1. Turn the Series 3a off, if it isn’t already, and connect it to your Linux system.
  2. On the Series 3a:
    1. Press [Esc] to turn the Series 3 on and then [U]+[P] (or [Menu], select „Special“, „Remote Link“ – in German the menus are called „Extras“, „Rechnerkopplung“).
    2. Set „Remote Link“ to „On“ and „Baud rate“ to 19200. Confirm these settings by hitting the „Enter“ key. Note that the Serial Link is powered by the Series 3a, so may drain your batteries faster than expected.
  3. On the Linux system:
    1. In one terminal, start the NCP daemon as a privileged user, with the device name matching your USB adapter and the baud rate set to the same value as on the Series 3a:

      $ sudo ncpd --dontfork --serial=/dev/ttyUSB0 --baudrate=19200

    2. In a second terminal, you can now use plpftp to transfer files from and to the Series 3a into the local directory. Common FTP commands will work, „dir“ and „ls“ list directories, „cd“ changes directories, „get“ downloads a file from the Series 3a to Linux and „put“ uploads a a file from Linux to the Series 3a. Example session (on a German environment):

$ plpftp
PLPFTP Version 1.0.13 Copyright (C) 1999 Philip Proudman
 Erweiterungen Copyright (C) 1999-2002 Fritz Elfert
                   & (C) 1999 Matt Gumbley
                   & (C) 2006-2008 Reuben Thomas
Dies ist freie Software. Sie können Sie unter den Bedingungen
der GPL weitergeben. Siehe die Datei COPYING im Paket.

FTP Oberfläche gestartet. Geben Sie „?“ ein, um Hilfe zu bekommen.
OwnerInfo lieferte Fehler unit disconnected
Psion Ordner ist: „A:\“
> cd M:\
> ls
drw—-nb- 0 So 04 Jul 1993 13:10:32 DAT
drw—-nb- 0 So 04 Jul 1993 13:12:16 OPL
drw—-nb- 0 So 04 Jul 1993 13:12:16 WDR
drw—-nb- 0 So 04 Jul 1993 13:12:58 WLD
drw—-nb- 0 So 04 Jul 1993 13:13:24 AGN
drw—-nb- 0 So 04 Jul 1993 14:39:46 WRD
drw—-nb- 0 So 04 Jul 1993 14:42:04 SPR
drw—-nb- 0 Do 16 Dez 2021 22:23:02 ENROUTE
drw—-nb- 0 Do 30 Dez 2021 14:29:18 OPD
drw—-nb- 0 Do 30 Dez 2021 14:29:20 GPK
drw—-nb- 0 So 16 Jan 2022 11:20:26 SCR
drw—-nb- 0 So 16 Jan 2022 11:20:26 SCO
> cd SPR
> dir
-rw–a-nb- 199 Do 16 Dez 2021 22:31:42 TABELLE.SPR
-rw–a-nb- 14861 Mo 19 Apr 1999 20:00:46 MINVERZ.SPR
-rw–a-nb- 13913 So 16 Jan 2022 12:35:16 MINVER.WKS
Übertragung abgeschlossen, (14861 Bytes in 9.70 sek. = 1532.06 cps)
Übertragung abgeschlossen, (13913 Bytes in 9.4 sek. = 1539.05 cps)
> cd B:\
> dir
drw—-nb- 0 Fr 12 Dez 1997 11:33:08 DAT
drw—-nb- 0 Di 07 Sep 1999 13:25:08 WDR
> ls DAT
-rw–a-nb- 1370 Mi 07 Jul 1999 14:53:30 �RZTE.DBF
-rw–a-nb- 381 So 12 Apr 1998 15:06:44 KURHAUS.DBF
-rw–a-nb- 642 Di 09 Dez 1997 16:48:56 NOTRUF.DBF
-rw–a-nb- 806 Do 27 Nov 1997 17:05:48 SPIT�LER.DBF
-rw–a-nb- 315 Do 27 Nov 1997 16:51:16 VETRIN�R.DBF
-rw–a-nb- 5290 So 04 Jul 1993 13:14:30 DIV.NUM
> cd DAT
Übertragung abgeschlossen, (381 Bytes in 0.46 sek. = 828.261 cps)
> bye

Any media in the two SSD slots of the Series 3a can be accessed as drives A:\ and B:\ just as on the Series 3a itself. Drive C:\ offers the contents of the serial link (includes the „Comms“ software, a serial terminal emulator). The internal RAM drive is called M:\ in plpftp.

The directories represent the different applications and each contain the applications file types, as listed on page 241 in the Series 3a User Guide:

Type of fileDirectoryFile extension
Printer drivers\WDR.WDR
Word templates\WDR.WRT
Sound files\WVE.WVE
OPL modules\OPL.OPL
translated modules\OPO.OPO
other OPL files\OPD.ODB, .PIC
programs/OPAs\APP, \IMG.APP, .IMG, .OPA
System screen lists/groups\APP.ALS, .GRP

To read the files on Linux, you can use psionio for conversion of database files – or just extract the text from these using the strings command. For the spreadsheets, save them as Lotus 1-2-3 WKS or WK1 on the Serieas 3a and LibreOffice can still open these (but not write them).

Further Reading

You can use the Serial Link to go online, either by using the Comms application on the Series 3a as a terminal emulator to access your Linux system and it’s applications or by using the „Web“ browser, which is part of the PsiMail Internet application suite, over pppd running on the serial attached Linux host or a NodeMCU WiFi microcontroller:

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