Toshiba HX-31
This page was last modified 11:35, 29 January 2020 by Rderooy. Based on work by Mars2000you and Gdx.




The HX-31 looks identical to the HX-30 with its black case, but it has more RAM and a built-in firmware. It is not possible to add an RS-232C interface. This machine was released for the Japanese market with the "Pasopia IQ" label.

Although it's a MSX1 computer, it can probably use a part of the MSX memory to create a RAM-Disk or Memory Disk (feature generally reserved for MSX2 and higher computers), just like the HX-32.

Brand Toshiba
Type HX-31
Year 1985


Region {{{region}}}
Original price ¥49,800
RAM 64kB
Media Cartridges
Video  ? Toshiba T6950
Audio PSG (YM2149F)
Chipset  ? Toshiba TCX-1012/TCX-1008
Extras Japanese Word Processor, Printer BASIC, MemoryDisk BASIC
Emulation ROM dump needed. See this thread for details


The built-in firmware is probably version 2.3 of the Japanese Word Processor, that is also available on the HX-32. From BASIC, the firmware can be launched with CALL JWP or _JWP. It includes the additional BASIC commands for Memory Disk and printer.

However, you need to have the HX-M200 Kanji ROM Level 1 in one of the cartridge slots.

It is possible to use other Kanji Roms, but if you use the Sony HBI-K16 Kanji ROM Level 1, CALL JWP leads to a I/O device error. To bypass this problem, an addendum to the manual of the Sony cartridge gives the solution:

10 FOR I = &H9080 TO &H9120 : POKE I, &HC9 : NEXT I


Toshiba HX-31
Toshiba HX-31 right side
Toshiba HX-30/31/32 manuals
Toshiba HX-31 back


The HX-31 is a MSX1 computer with 2 cartridge slots (one at the top, one at the back) and a Z80A from Sharp (LH-0080A). The 2 joystick ports are located on the right side of the computer.