Russian version is here

Lately Personal Digit Assistants (PDA) have become quite a popular product. There is a wide range of such devices. But only one could attract my attention. This is Psion Series 5. Frankly speaking, there are a lot of Psion devices, but only this one was available for us to buy. I'm not going to describe whole the Psion's family, you could do it yourself on This article has other aims.

Most PDA, and Psion is not an exception, have a software for PDA<->PC data transfer. So Psion has its own software named PsiWin. As you can see from its name, this program is intended for MS Windows 9X (NT). But my main operation system is OS/2. It is very inconvenient to reboot into Windows each time I need to get file or two from/to Psion. Of course, there is not any program for OS/2, and Symbian (who produces this software) isn't going to create it. So, this article is about Psion project, Psion to OS/2 connectivity program, which I developed myself.

It's the best Microsoft practice to hide interfaces descriptions and protocols specifications and Symbian successfully follows this practice. Thus, all information about Psion link protocol has been obtained by different people (see credits) by reengineereing methods and something I have had to investigate by myself. But at present, Alexander Thoukydides has collected all information and written detailed specifications for Psion's protocols, and you can get it on in English, or my Russian translation on

Project went through at least three stages. First of all I tried to copy PsiWin functionality, it was quite difficult (simultaneously write PM-interface and serial link interface) and hasn't led to any results. This version has never worked. Then I found several versions for several different platforms (BeOS, Linux, etc.) They are open projects. So, I could get acquainted with other decisions. The second realization was a ftp-like text interface communication program. The first public version was realized at the beginning of the year 2000. You can get the latest version from There are two programs: psiftp.exe and psiprn.exe. The first of them is a file transfer utility. The second is a print redirector, because not all Psion users have a printer with infrared or serial link support. When I had developed psiftp I checked it with Psion Series 5 and some Psion emulators - Series 3, Sienna and Workabout. Nowadays, as far as I know from the psiftp users, it works with Psion Series 5Mx, Psion Revo, Psion Series 7 as well as with all the previous.

Some features of the psiftp are mentioned below:

The screen of the psiftp looks the following way:
psiftp screen
I know it's a pity, but there is still no full documentation for psiftp. But I'm ready to answer all your questions via e-mail.

The third try is, in my opinion, the most important. Because this is the plugin for the NetDrive. In this way, there is no difference between access to regular hard (network) OS/2 drives and Psion drives. You just mount Psion onto preferred directory.

ndcreatemp u:\MyPsion
ndmount psion u:\MyPsion PSICP=ibm-1251;PSICOM=com1;PSIBAUD=115200 rw
First parameter is a codepage used in your Psion. PSICOM is a com port name to communicate with. PSIBAUD is a connection speed (if isn't provided, plugin is trying to establish it automatically). Plugin shows Psion's drives as subdirectories in a mounted directory : C$, D$, Z$ (or M$... for early models). C$ is a regular Psion drive C:. And Z$ is a Psion's ROM. Yes, Psion's ROM is visible too. Thus you can use your favorite filemanager. I'm using File Commander to copy files from/to Psion. You can do it even with WorkSpace via mouse drag'n'drop. I have got working version already, and I'm just waiting for the version two of the NetDrive to go out. NetDrive with Psion plugin has (it seems to me) much seamless design than Symbian's own program for Windows (PsiWin). Most of all I'm proud of the size of this plugin - about 97k plugin itself and about 250k all NetDrive. Now there is only one restriction in the plugin - only one process can get access to Psion at the same time (I didn't make it reentrant yet). Psion plugin and the last version of the PsiFtp are using the same engine (library). That provides a simple way to upgrade both on them. Here is the screenshot with Psion mounted :
Psion disk mounted with NetDrive
This project wouldn't be done without support of many people. First of all I want to thank NetDrive development team and particularly Vitali E. Pelenyov , Alexander Thoukydides for full Psion's protocols description, OS/2 Underground team and Dmitry Ban for granted Web-site space and performed editor's job. And all OS/2 users who sent me their bug-reports.


NetDrive Psion plugin


psiftp v1.0:, 1.2Mb
Psion OS/2 NetDrive plugin v1.0b:, 83k

psiftp v1.2:, 1.3Mb
Command line switch '-r' is added. For switching off RPC support for old Sibo machines (which haven't got SYS$RPCS.IMG properly installed. Consult your Psion User's manual for details).
Rexx interface is released.
Port of PsiConv wasn't changed, I'm waiting for RTF suppord released.

[15.10.2001] psiftp v1.3:, 1.3Mb
Improved performance (about 10-15%). Fixed some little bugs in RPC. RPC with my Sibo emulator is unstable. If you are interested in RPC support for Sibo machines drop me a e-mail. Fixed error in the Rexx example for RPC., 110k
NetDrive plugin to get access to Psion PDA disks as to ordinary OS/2 drive (now with icons :-)

Andrei A. Porodko (AKA Andy A. Porro)