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[IBS/Radix FW60] Very ruggedised, handheld CP/M computer

clueless_engineer (Brett)

clueless_engineer (Brett)

Experienced Member
Joined
Nov 9, 2023
Messages
173
Location
Port Macquarie, Australia
Hi,

Handheld computers running CP/M or DOS are always interesting to me. I've tried to document something about this particular British machine running CP/M 2.2.

It was never meant to be repaired or serviced so this investigation was quite destructive. But I do intend to (try to) resurrect the machine as discrete boards.

I believe it was original developed by a company called "Immediate Business Systems plc" (or IBS) which later became "Radix Micro Devices plc" ... that is a guess. Radix was later acquired by a US company called "Elecsys Corporation" in 2007.

There are a few of these devices available on ebay - the device I have originated from Greece. These listings also seem to hint that the "FW" in the model name refers to "Field Worker".

Here are the stats that I've discovered so far:
  • Hitachi HD64180 CPU (apparently licensed back to Zilog as the Z61480 which became the Z180)
  • Hitachi HG61H15 series ASIC (© IBS plc)
  • NEC D7506G 4-bit microcontroller (for keyboard?)
  • 20x4 LCD
  • 32KB EPROM (?) with CP/M 2.2 plus application software (?)
  • 128KB RAM
  • 128KB or 1MB RAM disk (battery backed)
  • 6-pin circular RS232 serial port
  • 12-pin circular modem port
  • 5 col/8 row keyboard with additional button in the battery compartment (full reset?)
  • 3.6V 600mAh rechargeable battery pack (three Sanyo N-600A cells)
  • 3.6V non-rechargeable battery (Saft LS14500) for RAM backup
  • two 3V rechargeable button cells (Sanyo ML2016) on processor board
It runs on three NiCd batteries and has three further internal batteries: two rechargeable CR2016 on the processor board and a Saft LS14500 very-long-term backup battery for the RAM disk & RAM. This Saft battery is non-rechargeable and apparently has a life of up to 20 years (depending on load). The one in my machine is dated 1997 and has no charge left.

The machine was definitely designed to have a life of several years and take a lot of abuse, never requiring repair - the RAM backup battery would've been impossible to replace.

I have started a Github repository here - so far (24/8/2026) I have just the keyboard matrix but plan to add images of the boards & ROM dump.

I have two YouTube videos so far:

Brett.

Radix_FW60_small.png
 
Last edited:
Very nice work, Brett! I love to see any of these unusual/non-stereotypical machines being documented and preserved.

As a side note, I've watched a number of your videos. Excellent work, and I appreciate the effort that you put in.

- Alex
 
ajacocks said:
Very nice work, Brett! I love to see any of these unusual/non-stereotypical machines being documented and preserved.

As a side note, I've watched a number of your videos. Excellent work, and I appreciate the effort that you put in.

- Alex
Click to expand...
Thank you sir, appreciate the feedback. I know they are pretty low-effort, but hopefully they've improved over time!

I'm hoping to get my hands on another machine, with a manual, so I can scan that in at least.

Doing analysis of the ROM with Uncle Claude, it seems to think that some font information was stored in the RAM as it couldn't find any Greek characters in the ROM ... ?

The ROM, incidentally, is apparently Personal CP/M-80 ... a ROM version compatible with CP/M 2.2 ... ?
 
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