The Psion MC400 EROS – Tandy TRS-80 model 200 replacement?

This was an unexpected eBay find – the “AAPROVED for connection to telecommunication systems…” sticker immediately caught my eye…

What do we have here?

Upon first inspection it seems to be a standard V2.60F MC400 without any of the standard apps, just this mysterious EROS OPO on a 256k Flash SSD…

I’m guessing this was The Yorkshire Post’s “YP6” machine back in the day. The keyboard looks & feels like it’s taken some hammer over the years and the screen has some slight damage too.

Keyboard feels soggy…
LCD bleed

According to this press release I found from 1993 it appears the EROS system was a proposed replacement for an old Tandy/Radio Shack TRS-80 variant that was apparently much loved by journalists:

My favourite quote from that article: “…spent UKP20,000 in developing the character-based software for the machine after deciding that Psion’s original graphical user interface was too alienating to journalists” LOL. I guess that’s why they didn’t supply any of the other (“MC Word” version) standard apps.

So it was deisgned to be a field text processor with modem and software for delivering articles into a newspaper’s central systems. Created and sold directly by “Design System Services Ltd” in 1994/5 under contract from United Newspapers.

OPL text console goodness…

EROS was written entirely in OPL, one main OPO calling any of 19 other OPM modules however the official PSION Text Processor & Data apps are included on the disk, but they’re called directly from options in the main EROS OPL routine.

DBA.APL, PDB.APL & TXT.APL are standard Psion apps, just renamed and called from the EROS OPL
EROS main menu – land line or Mobidem radio data network connectivity
Handy hints to enlarge or exit 🙂
text-based file selection
ready to upload – 27 years later 😉
mandem use mobidem…
The white heat of 1995 comms technology – 2400 Baud 🙂

The machine also came fitted with what appears to be half of the Psion “MC Quad Modem” (so called as it supported 4 standards: V21, V22, V22bis & V23) – I suspect there was a soap-on-a-rope cable (the “PSION DCLI” mentioned on the sticker!) that contained the line interface electronics and this MC module is only serial data + power.


Ironically this fascinating piece of British computing history arrived wrapped in a Tandy 200 leatherette pouch 🙂


Inside the “MC Quad Modem” – ubiquitous Intel 28F010 flash chip, Toshiba Z80 and RAM and tiny piezo speaker for the authentic dial-up squeaks & squawls. Teridian “single chip modem”s in the 73K322L & 73K224L packages.

Published by zedstarr

Chilled out human being, doing techy stuff.

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