The Psions have both serial and infra red ports. Either can be used for connectivity, but most connectivity programs currently only have features for the serial port connection.
Armin Podtschaske x-rayed the "honda" connector.
Pin 1 is on the top and pin 15 is on the bottom. Only pins 2 through 8 and 15 are connected.
See Werner Heuser's Infrared HOWTO for information about using the Linux IrDA driver with a Psion. It is possible to beam files from Psion 5 (mx) via Linux-IrDA to a Linux System. The irda-utils include a special client psion5.c which can beam files between them.
There are two builtin software methods to use the communications ports. The first is the remote link, <ctrl>-l from the main file menu, which can be set to serial, infrared or off.
EPOC also provides the program comms. The remote link must be set to off for the comms program to have access to the serial port.
plptools was originally developed by Fritz Elfert, who had merged plp and p3nfs/p5nfs. plptools is currently being worked on by members of the PLP Tools project.
plptools comprises of 3 different programs. ncpd provides a socket connection to the Psion. plpnfsd provides mounted filesystem access to the Psion and plpftp provides ftp access to the Psion.
ncpd [-V] [-v logclass] [-d] [-p <port>] [-s <device>] [-b <baudrate>]
plpnfsd [-v] [-V] [-p port] [-d mountdir] [-u user]
First start ncpd get it to listen on a port (7501 by default) for connection requests. Then, start either plpnfsd or plpftp. plpnfsd defaults to mount the Psion under /mnt/psion.
p3nfs mounts the psion drives over the serial cable at /psion.stand/mnt, by default.
Matt Gumbley originally started ncp for use with his Psion Series 3. Now that he's working on plptools, you should use that :). However, ncp might still be of interest to users of a Psion Series 3, which this HOWTO doesn't cover :). Matt's ncp page also has information about the plp protocol.
Psiconv translates Psion Word documents or TextEd files (as used by the OPL editor, for example) to HTML (3.2 or 4.0) or plain text. It can also translate Sketch files and MBM files to almost any graphics format. A description of the Psion files formats is also included.
psiontobbdb converts Psion vcard format from the EPOC Contacts application to emacs BBDB format.
psiontognomecard converts Psion vcard format from the EPOC Contacts application GnomeCard vcard format.
kab2psion is a small utility written in perl to create a CSV file from the KDE addressbook.
PsiLin (in French, short english version) is a GTK-based graphical frontend for many programs which connect Linux to Psion. It also works for Series 3*.
The EPOC SDK works on Linux via WINE, see Olaf Flebbe's web page for instructions on how to get it working.
xmakesys is a perl utilility that parses Psion's .pkg files and outputs .sis files.
hermes is a fully featured vt100 emulator.
Olaf Flebbe has perl running under EPOC.
Duncan Booth has python running under EPOC. (link currently down)
Otfried Cheong also has a port of python for EPOC.
Tim Wentford has gotten Bprolog working on the Psion 5*.
Nick Murray has created Shell5, which is a command line interpreter which allows basic file operations as well as some sophisticated functions such as command history, filename expansion, batch file support, input and output redirection, pipe like feature :), aliases and shell variables, keyboard remapping and macros and UNIX or DOS syntax for pathnames.
E-shell comes with the SDK and is a DOS-like shell environment from the EPOC SDK. It provides ways to launch programs from a command line; to check for file system corruption; to create, edit and display plain text files; to check on currently active processes and threads. The former link to download the shell itself has been removed.
c2f converts the Psion contact file to a comma delimited format.