Put a Psion on the modern internet from a Mac or a Linux PC, over the serial cable or, for the netBook Pro, over your network -- which a Windows PC can serve too.
PsionNet does two things. It brings up a PPP link over RS-232 so the Psion gets a real IP address and routes through your computer, and it runs a proxy that terminates modern TLS and rewrites pages into something the device's browser can actually parse. A netBook Pro with a network card needs no link at all: the proxy listens on the computer's own network address instead.
It supports three quite different browsers: the EPOC handhelds' ROM browser, which needs HTML 3.2; the netBook Pro on Windows CE, with Pocket Internet Explorer; and the netBook Pro running PsionLX, Psion's own Linux, with Firefox 1.0. The proxy detects which is asking and shapes its output to suit.
For the netBook Pro running PsionLX it is also a Spotify speaker. A Spotify app on the netBook Pro browses your library and plays it, with PsionNet doing the part a 2005 machine cannot: talking to Spotify. See Spotify on the netBook Pro.
And it is PsionLX's software library: Psion's TASKS screen offered "Find new software" in 2005 and never implemented it. Now it installs programs, games and fonts from the RetroTechCollection archive, which PsionNet fetches over the HTTPS the netBook Pro cannot speak. See Software for PsionLX.
It comes as a Mac app, a Debian package and a Windows installer, each with everything it needs inside. No terminal required.
Status: works, and used in anger. The link, the proxy and the app are all verified end to end on real hardware, on both a Series 7 and a netBook Pro (Windows CE, dial-up).
Spotify on the netBook Pro works on the real machine (4 October 2026), over network mode. Still untried on hardware: browsing with PsionLX's Firefox through the proxy, and Windows CE over the network; see What has been tested.
EPOC Release 5 shipped a complete TCP/IP and PPP stack, so a Psion from 1999 can still get online. The networking was never the problem; the web was.
The ROM browser has no SSL at all. The string https does not appear once
in the entire 16 MB ROM, so there is no scheme handler to fix and nothing to
negotiate. It has no CSS engine, no JavaScript, no PNG decoder, no gzip, and an
ISO-8859-1 character set. In 2026 that means essentially nothing on the public
web will load.
The proxy does the TLS on your computer and hands the Psion plain HTTP that it can render, so an unmodified machine browses the real internet.
Hardware
- A Psion running EPOC Release 5: Series 5mx, Series 7, netBook, or Revo. (The Series 5 classic runs ER3 and is not covered.)
- Or a Psion netBook Pro, which runs Windows CE 4.2 .NET rather than EPOC. It connects over the same serial cable, but as dial-up to an emulated modem rather than a direct link. Pick it in the app's Device menu.
- Or a netBook Pro on your network, running Windows CE or PsionLX, with a network card (wired or wireless) on the same network as the computer. No cable.
- The Psion's own serial cable. It is already wired as a null modem, so no crossover adapter is needed.
- A USB-to-RS-232 adapter. Anything with a working macOS driver: FTDI, PL2303, CH34x, or an ATEN UC-232A.
Software
One of these, from the latest release. Each bundles its own Python, Tk and dependencies, librespot included.
| Computer | Download | Serial cable | Network |
|---|---|---|---|
| macOS 11 or later, Apple Silicon or Intel | PsionNet-1.3-macOS.zip, signed and notarised |
yes | yes |
| Linux: Debian 12 or later, or Ubuntu 22.10 or later, on a 64-bit PC | psionnet_1.3-1_amd64.deb |
yes | yes |
| Windows 10 or 11, 64-bit | PsionNet-1.3-Windows-Setup.exe |
no | yes |
Windows has nothing like pppd, the program that runs the PPP link on macOS and
Linux, so on Windows PsionNet serves only the netBook Pro on your network
(Windows CE or PsionLX), with the proxy, Spotify and the software library. The
Series 5mx, 7, netBook and Revo need the serial cable, and so a Mac or Linux.
- macOS: unzip, and drag PsionNet to Applications.
- Debian and Ubuntu:
sudo apt install ./psionnet_1.3-1_amd64.deb, then find PsionNet among your applications. For the serial cable, add yourself to the groups that may use serial ports and run pppd, so that connecting asks for no password:sudo usermod -aG dialout,dip $USER, then log out and in again. Without them, PsionNet asks for your password through the system's dialog. If ufw is on, allow the proxy in from your network (sudo ufw allow from 192.168.1.0/24 to any port 8080 proto tcp, and port 8899 udp for discovery), and the Psion out (sudo ufw route allow in on ppp0). - Windows: run the installer. It is not signed, so SmartScreen says "Windows protected your PC": choose More info, then Run anyway. The installer lets PsionNet through Windows Firewall on private networks, so your network must be set to Private (Settings > Network > the network > Private), or the netBook Pro cannot reach the proxy.
To run from source instead, you need Python 3.10+ with Tk, and
pip install -r proxy/requirements.txt. Spotify also needs librespot
(brew install librespot on a Mac).
For Spotify
- A Spotify Premium account. Spotify plays only Premium accounts through Connect speakers like this one.
- A Spotify developer Client ID, which is free: see Spotify on the netBook Pro.
- Open PsionNet.
- Pick the serial port. The app marks the one that looks like a USB adapter and tells you if something else is holding it.
- Press Connect. On a Mac, the first time, it offers to install the PPP configuration; it asks for your password to start the link (on Linux, not at all once you are in the groups dialout and dip).
- On the Psion:
- System → Tools → Link to desktop (or Remote link) → set Link = Off, so the port is free.
- Control panel → Dialling → set a location. Nothing is dialled, but skipping this gives "Connection information not found".
- Control panel → Modems → choose Direct cable connection, 115200, hardware (RTS/CTS) flow control.
- Control panel → Internet → new service, Connection type: Direct. Tick Get IP address from server and Get DNS address from server.
- Open Web on the Psion to bring the link up.
- Start the proxy in the app, then on the Psion set
Web → Tools → Proxy server settings →
10.0.2.1, port8080. - Browse to
http://psion/for the home page and search.
- Join the netBook Pro to the same network as the computer running PsionNet.
- In PsionNet, set Device to netBook Pro (CE, network) or netBook Pro (PsionLX, network).
- Under Listen on, pick the computer's address on that network, for
example
en0 192.168.1.4on a Mac. Only that network, and the computer itself, may use the proxy. - Press Start under Web proxy. The status line shows the address.
- Point the netBook Pro at it:
-
Windows CE: Internet Explorer's Internet Options → Connection → use a proxy server, that address, port
8080. -
PsionLX: once, in Terminal (PROGRAMS → OTHER), with that address:
su wget -O - http://192.168.1.4:8080/lx/install | shPsionNet's status line shows the exact command. It installs "Find new software" and a helper that, at every login, finds PsionNet and points Firefox at it, so there is no proxy setting to type or keep up to date.
-
- Browse to
http://psion/as before.
There is nothing to connect: the Connect button is unused in network mode.
pppd, which macOS still ships, talks PPP over the serial line. The Psion's
ROM has a Direct cable connection modem profile and a Connection type:
Direct option, so there is no modem handshake to emulate: it opens the port and
starts LCP.
A Mac NATs the link out through its own uplink with a pf anchor, loaded into
a child anchor under Apple's existing hooks so /etc/pf.conf is never touched.
Linux does the same with an nftables table of its own, made when the link comes
up and deleted when it goes down.
Serial pppd on Apple Silicon appears to be undocumented territory. No prior
report of it working turned up anywhere. It does work.
Requests arrive as ordinary HTTP. The proxy fetches over modern TLS, then:
- prunes hidden markup:
hidden,aria-hidden, inlinedisplay:none. On BBC News that is 52% of the page, mostly four near-identical copies of the same story block shipped for different screen widths - rewrites to HTML 3.2 for EPOC, against element and attribute whitelists read out of the Series 7 ROM's own parser tables. The netBook Pro gets HTML 4.01 and keeps its stylesheets instead, because it can render them
- transcodes images to non-interlaced GIF or baseline JPEG, the only two formats the ROM can decode
- downgrades text to the byte range where CP1252 and ISO-8859-1 agree, for EPOC only. The netBook Pro reads UTF-8, so its text is left alone
- filters CSS to the IE6 subset for the netBook Pro, then drops every
classno surviving rule uses. On BBC News that is 190 KB of stylesheet down to 32 KB and 66 KB of dead attributes down to nothing - relativises same-origin URLs.
hrefs are 26-48% of output bytes
| Page | Upstream | To the Psion | Wire time |
|---|---|---|---|
| BBC News | 1,041 KB | 31 KB | 3.0 s |
| The Guardian | 1,496 KB | 48 KB | 4.7 s |
| Wikipedia article | 100 KB | 24 KB | 2.3 s |
| Hacker News | 34 KB | 19 KB | 1.8 s |
Measured link throughput is 10,650 octets/s on the EPOC link, so roughly 100 KB per ten seconds. The netBook Pro's dial-up link runs at 19200, about 1.9 KB/s, so its pages are budgeted generously but arrive slowly: a full BBC News front page is about 70 seconds.
Which profile you get is decided by the User-Agent. There is nothing to configure. See proxy/README.md for the full comparison and how the CE profile was measured.
The netBook Pro cannot talk to Spotify itself. Its newest TLS is 1.0, and no Spotify client was ever built for its 2005 ARM Linux. So the work is split:
- On your computer, PsionNet runs librespot, an open-source Spotify Connect player, as a speaker called netBook Pro, signed in to your account. It encodes what the speaker plays as 128 kbit/s MP3 and streams it over plain HTTP, and it answers the app's requests for your playlists, search results and cover art.
- On the netBook Pro, the Spotify app (installed from PsionLX's Find new software, then in PROGRAMS → OTHER) shows your Liked Songs and playlists, searches, and controls playback. It plays the stream through the GStreamer already in Psion's image, and only while the netBook Pro is the speaker Spotify is using.
Because the netBook Pro is an ordinary Connect speaker, the Spotify app on your phone or computer can also send music to it.
- Create a Spotify app at https://developer.spotify.com/dashboard. Any name
will do. Add the redirect URI
http://127.0.0.1:8897/callbackexactly, tick Web API, and save. Copy its Client ID. - In PsionNet, set Device to netBook Pro (PsionLX, network). A Spotify box appears: paste the Client ID and press Log in. Your browser opens on Spotify's sign-in page; approve it.
- Start the proxy. Within a few seconds the Spotify box reports the netBook Pro speaker online.
- On the netBook Pro, install Spotify from Find new software (TASKS) if it is not there yet, then open it from PROGRAMS → OTHER. It finds PsionNet on the network by itself; if it cannot, it asks for the computer's address.
The speaker then signs in once more, on its own: the first time the proxy starts, librespot opens a Spotify page in your browser. If you are already signed in to Spotify there it completes by itself and says "Go back to your terminal"; close the tab. Spotify accepts only librespot's own sign-in for a speaker, so the login with your Client ID (which runs the library, search and controls) cannot be reused for it. Both are remembered.
- The sound lags the buttons. The stream is buffered at both ends so that a busy network does not make it stutter.
- The computer does the work and must stay awake while you listen.
- Your Spotify tokens are kept in
~/Library/Application Support/PsionNeton a Mac,~/.config/psionneton Linux and%APPDATA%\PsionNeton Windows, readable only by you. Log out deletes them.
The full PsionLX image adds games, tools, Psion's Agfa fonts and Find new software to Psion's own image. Those programs, and the Spotify app, are in the PsionLX-Software folder of the RetroTechCollection archive, as packages for Psion's own package manager, so any PsionLX card can have them:
http://<this computer>:8080/lx/installis the installer described above.http://<this computer>:8080/lx/software/...hands the netBook Pro files from https://archive.retrotechcollection.com/PsionLX-Software, fetched over HTTPS and passed on byte for byte. It serves that one folder only.- On the netBook Pro, Find new software, on the TASKS screen where Psion put it, lists everything with icons and descriptions, and installs or removes it through Psion's ipkg. PsionLX's root password is empty, so it asks for nothing; if a root password has been set, it asks for that.
Being honest about the limits:
- Google returns nothing, on either device, for two different reasons.
EPOC and any modern User-Agent get a JavaScript-only results page: about
91 KB of script and 102 characters of visible text. Windows CE is blocked by
name before a line of script is sent, with 2,318 bytes reading "Your browser
isn't supported any more". Accepting the cookie notice reaches the same
block, so consent is not the gate, and Pocket IE having a JScript engine
does not help when the page is refused outright.
google.comis intercepted and a working search page served instead, backed by DuckDuckGo, Marginalia and wiby. - Google will never look like Google. Its identity is entirely CSS, and there is no CSS engine. Pages render as structured documents, not designs.
- Forms work; POST does not. Search boxes submit as GET.
- No JavaScript, ever, on either device.
- Some sites refuse proxied requests outright and are short-circuited rather than left to time out.
Browsing is a charming demo. The genuinely useful thing is that a Series 7 is an excellent VT100 with a full-size keyboard and all-day battery.
On real hardware: the serial link, the proxy and the app, with a Series 7 and with a netBook Pro on Windows CE over dial-up. And Spotify: on 4 October 2026 a netBook Pro running PsionLX played real Spotify through its own speaker, from PsionNet in network mode on the same network. The app was installed over the network, found PsionNet by itself, and drove playback; the sound went through Psion's own GStreamer and sound server, with the 400 MHz XScale's load average about 2 while playing.
Before that, in the emulator and on this Mac:
- The netBook Pro's Spotify app, inside a PsionLX image, booted under
QEMU with an emulated network, against
--spotify-demo, a stand-in for Spotify with invented tracks and plain tones. It was opened from its PROGRAMS icon, found PsionNet on the network by itself, listed the library, played a track on a double-click, showed its cover, followed playback, and searched. - The netBook Pro's sound path, Psion's own GStreamer 0.8
(
gnomevfssrc ! mad ! audioconvert), decoded the stream in real time in the emulator: 24.6 s of the expected 440 Hz tone in a 25 s run. The emulator has no sound hardware, so the last step,esdsinkto the speaker, waited for the real machine. proxy/tests/test_network.py: the PsionLX profile, the address allowlist, discovery, and every Spotify request against the stand-in.- The built app: its proxy serves the Spotify requests in network mode, and the bundled librespot 0.8.0 runs.
Learned on the real machine: the login with a Client ID runs the library,
search and controls, but Spotify refused librespot as a speaker when handed
that login's token (INVALID_CREDENTIALS). The speaker therefore signs in with
librespot's own sign-in, which Spotify accepts.
Not yet tried on hardware: browsing the web with PsionLX's Firefox through
the proxy (its profile is tested on this Mac only), and Windows CE over the
network (its profile is the one tested over dial-up). The Windows and Linux
versions have been tested by the build workflow only, not yet with a Psion:
on Linux the serial link was tested over a pty with a second pppd standing in
for the Psion, for EPOC's direct link and for Windows CE's dial-up through the
fake modem. The hardware test ran
PsionNet from source; the app bundle with Spotify in it has been checked only
as a scratch build, with the stand-in.
python3 app/main.py # run the GUI from source
python3 proxy/run.py --host 127.0.0.1 # run just the proxy, test from this computer
python3 proxy/tests/test_units.py # transforms, offline
python3 proxy/tests/test_wire.py # end-to-end, hits the network
python3 proxy/tests/test_startup.py # launches run.py for real
python3 proxy/tests/test_network.py # network mode, discovery, Spotify API
# network mode on this computer's LAN address, with a stand-in for Spotify
python3 proxy/run.py --host 192.168.1.4 --allow 192.168.1.0/24 --spotify-demo
sh bin/build-app.sh # build PsionNet.app with PyInstaller
sh bin/sign-app.sh --notarize # sign and notarise (needs your own Apple ID)
# Windows and Linux: PyInstaller builds dist/PsionNet, then
python -m PyInstaller PsionNet.spec
iscc /DAppVersion=1.3 packaging\windows\psionnet.iss # the Windows installer
sh packaging/linux/build-deb.sh # the .deb, on DebianPyInstaller cannot build for another system, so the Windows installer and the
Debian package are built by a workflow on
GitHub's machines, which also tests them: the test suites, the built program's
proxy and Spotify stand-in, its window, the installer installed and removed, the
package on clean Debian 12 and 13, and the serial link end to end on Linux, over
a pty, with a second pppd in a network namespace standing in for the Psion.
test_wire.py drives the proxy with the exact bytes a Series 7 sends
absolute-URI request line, User-Agent: EPOC32-WTL/2.0 (VGA), empty
Accept-Encoding. It asserts the reply is HTTP/1.0, unchunked, uncompressed,
charset=iso-8859-1, free of C1 bytes, free of https://, and free of any tag
outside the ROM's element table.
More detail in app/README.md and proxy/README.md.
pppd needs root; the proxy does not. Only the pppd invocation is elevated,
through the standard macOS authorisation dialog. Nothing persistent is
installed: no sudoers entry, no LaunchDaemon, no setuid helper. The cost is
a password prompt on connect and disconnect.
On Linux, Debian's own pppd is made to be run by members of the group dip,
with the root-owned peer file supplying the options that need root; the port
needs the group dialout. A user in both connects with no prompt at all.
Otherwise PsionNet asks through polkit (pkexec), the Linux equivalent of the
macOS dialog. The Debian package installs /etc/ppp/peers/psion and
psion-ce-modem, /usr/lib/psionnet/fakemodem.py, and two hooks,
/etc/ppp/ip-up.d/psionnet and ip-down.d/psionnet, which turn on IP
forwarding and NAT (nftables) for the Psion's link only, and put both back as
they were when it ends. On Windows nothing needs privilege beyond the
installer's firewall rule.
Installing the PPP configuration writes /etc/ppp/peers/psion,
/etc/ppp/peers/psion-ce-modem, /etc/ppp/fakemodem.py (the modem the
netBook Pro dials), /etc/ppp/ip-up, /etc/ppp/ip-down and
/etc/pf.anchors/psion.nat. Network mode installs nothing.
ip-up and ip-down are global hooks that pppd runs for every PPP session
on the machine, so both begin by checking for this project's own ipparam tag
and exiting immediately for anything else. bin/uninstall.sh removes the lot.
The proxy is an open forward proxy that strips TLS. Over the serial link it
binds the PPP address, or loopback when there is no link. Never 0.0.0.0.
It also refuses to fetch private, loopback or link-local addresses, so it
cannot be used to reach inside the network it runs on.
Network mode has to listen on the computer's LAN address, which everything on that network can reach. So it binds that one address, serves only the computer itself and the subnet of the interface it listens on, and refuses everything else with a 403; its discovery responder answers the same subnet only. Within that subnet it is still an open proxy, so use network mode on a network you trust, and stop the proxy when you are done.
The Spotify control requests need a header the netBook Pro's app sends and a web page cannot, so a page shown in the device's browser cannot drive your Spotify. That header is not a password: while the proxy runs, someone on the same subnet who knows the API could change what is playing, and the audio stream itself is open to that subnet.
GPL-2.0-or-later. PsionNet contains artwork derived from Reconnect, which is GPL-2.0-or-later, and icons from Psion/Symbian EPOC software.
See ACKNOWLEDGEMENTS.md for full attribution.