Setname:  comx35n   
Year: 1983
Manufacturer: Comx World Operations Ltd
Status: imperfect  badworks
Type: Home Computer
Parent: COMX 35 (PAL)
Emulation info
Overall emulation:  good   
Color emulation:  good  
Sound emulation:  imperfect  
Graphics emulation:  good  
Savestates:  unsupported   

Tech info
 Base hardware: (available in all slot configurations)
CDP1802 ("u3")cpu 2835000 Hz
Speaker ("mono")audio
RCA CDP1869 ("u2")audio 5670000 Hz
Wave ("wave")audio
Screen ("screen")raster horizontal 294 x 242 @ 60.114504
Media devices
quickload ("quickload") quickload quik comx
cassette ("cassette") cassette cass wav
BIOS options
basic100 COMX BASIC V1.00
basic101 COMX BASIC V1.01
RAM options
32K 32768
Software lists

 Optional hardware: (available with specific slot configurations)

 Configure the slot options for comx35n:
 Slot Value

Show detailed info about 'Slot Options' of this system
Slot options

NameValueCompatible device(s)
exp clmcomx_clm
 eb comx_eb
exp:eb:slot1 clmcomx_clm
 fd comx_fd
exp:eb:slot1:fd:wd1770:0 525qdfloppy_525_qd
 525sd35t floppy_525_sd_35t
exp:eb:slot1:fd:wd1770:1 525qdfloppy_525_qd
exp:eb:slot2 clm comx_clm
exp:eb:slot3 clmcomx_clm
 joy comx_joy
exp:eb:slot4 clmcomx_clm
 ram comx_ram

Romset info
ROM NameSizeCRC32SHA1Dump StateBIOS option
comx_10.u2116384 68d0db2d062328361629019ceed9375afac18e2b7849ce47goodbasic100
comx_11.u2116384 609d89cd799646810510d8236fbfafaff7a73d5170990f16goodbasic101


* CPU: CDP 1802 2 MHz
* RAM: 35 kb (up to 67 kb). 32 KB available for Basic programs
* ROM: 16 kb
* Text Modes: 40 columns x 24 lines. 64 upper case ASCII characters
* Graphic Modes: None, but 64 user programmable graphical characters
* Colors: 8
* Sound: 1 channel synthesiser - 8 octaves, 16 volume steps and special effects
* I/O Ports: Tape, Monitor, 44-pin Bus expansion
* Keyboard: Calculator type keyboard, 55 keys QWERTY, Carriage Return (CR), RT, ESC, SHIFT (x2), DEL
* Built In Media: None
* Built In Language: Basic
* Peripherals: Printer, disk-drive


Currently, MESS supports two regional variations of the COMX 35

* comx35p [Comx World Operations Ltd. COMX 35 (PAL)]
* comx35n [Comx World Operations Ltd. COMX 35 (NTSC)]

Both drivers support the emulation of a "cassette" (cass) device, for tapes in .wav format, and up to two floppy drive, "floppydisk1" (flop1) and "floppydisk2" (flop2), for disk images in .img format.

Also notice that a “quickload” (quik) feature is available for .comx files and that the “printer” (prin) is emulated as well.


This system requires full keyboard emulation to work correctly. At startup, full keyboard emulation mode is enabled by default. Whilst in full keyboard emulation mode, some key associated functionality may be disabled (like the ESC key for EXIT). The keyboard emulation mode is toggled using the "Scroll Lock" key (by default).


To enter 80-columns emulation, you have to mount the 80-column card in one of the slots and then to start the card. In order to do it, you can simply press TAB while in partial keyboard emulation mode and enter the "Driver Configuration" submenu. Once you have selected the 80-column card in one of the slots (e.g. slot 3), you can go back to emulation by pressing TAB and start the card by typing


Of course, if you have chosen a different slot "X", you will have to type "SX" in place of "S3".

BIOS options

Different versions of the BASIC roms are supported. You can switch between them, changing the -bios parameter. At command line, for both comx35p and comx35n,

"-bios 0" or "-bios basic100" = COMX BASIC V1.00

"-bios 1" or "-bios default" = COMX BASIC V1.01

RAM options

Different RAM configurations are possible for the comx35p and comx35n in MESS. You can switch between them, changing the -ramsize parameter. At command line, you simply have to add ''-ramsize ram_value'', where //ram_value// can assume one of the following values

32k (default)

Known Issues

The sound emulation of these systems is known to be Imperfect.

History and Trivia

Very little is known about this obscure and rare computer.

It was desgined by a Netherlands based company called NOXON AB, and was manufactured in Hong Kong by COMX WORLD OPERATIONS LIMITED.

There is no graphic mode, but user definable characters can be used to simulate graphics. The sound features are poor as there is only one single channel beeper. You can hear it when pressing a key. The Basic is very simple, with not a lot of specific statements, since there is not much to play with...

The keyboard is said to be waterproof (can someone test that for us?) and used goldplated contacts under the keys (if you've got one, you are rich :-)). There is a built-in joystick to the right of the keyboard (very easy to break), a bit like on the Spectravideo SV-318. And just above it, is the power Led.
A small thermal printer was available for the COMX 35.

The chosen CPU, the RCA CPD-1802, was also used in the RCA Studio 2 videogame system and a development/hobby systems using Chip-8, like the Cosmac RCA VIP. This 8-bit processor is still being manufactured in many forms, as it is radiation-resistant. It was also used as the heart of the Voyager, Viking and Galileo probes !

The COMX-35 did have a successor: the COMX-PC1. This was just a COMX-35 in a different housing.

(info from


* COMX Club Netherlands --
* COMX 35 at --

Other Emu

* COMX Emulator --

Edit the History info for this game.


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