Casio MX-101
This page was last modified 13:22, 26 June 2021 by Mars2000you. Based on work by Gdx and Takamichi and others.



The MX-101 is the same computer as the Casio MX-10 but with added antennas. It allows displaying an image on a TV screen by aerial UHF signal without needing a cable, although a cable can still be used instead.

The other characteristics of this computer are identical to the MX-10. The quality of the rubber keyboard is dubious and there is no built-in tape interface. In practice, using tapes requires a non-standard tape connector and an FA-32 CMT I/F package.

Joypad keys are arranged in a diamond-shape (instead of a circle) without the 'Joypad 1' indication. Together with the TR1 and TR2 keys on the bottom left of the computer, these are equivalent to a joystick inserted into joystick port 1. It is likely that only games that use the BIOS routines to handle the joysticks can use this internal joypad. Notably, BASIC games using the STICK command are supported. (Citation needed)

Apart from the 'Joypad 1' keys, the computer also features normal cursor keys arranged above the joypad keys.

It's possible to add two cartridge slots and a printer port by combining this computer with the KB-10 expansion unit. Without the KB-10 unit, which has its own power supply, an external AC power adaptor (AD-4175) is needed.

This machine was aimed at the Japanese market and available only in black.

Official price: ¥19,800 for the computer, ¥13,800 for the expansion unit and ¥3,000 for the tape connector adapter.

Brand Casio
Model MX-101
Year 1987
Region Japan
Launch price ¥19,800
RAM 16kB in slot 0 (with or without KB-10)
Media MSX cartridges
Video Texas Instruments TMS9118NL
Audio PSG (AY-3-8910 in MSX Engine)
Chipset Hitachi HD62003
Keyboard layout QWERTY/JP50on
Extras Two specific keys TR1 and TR2, Joypad 1 cursors, wireless TV connection, (with KB-10) third cartridge slot
Emulation ROM dump needed. See this thread for details.


Casio MX-101 with left antenna
Casio MX-101 (without antenna)
Casio MX-101 with all antennas
Casio MX-101 box and content
Casio MX-101 box
Casio MX-101 box (back)
Casio MX-101 manual
Casio MX-101 PCB
Casio MX-101 PCB back
Casio MX-101 left side
Casio MX-101 label
Casio MX-101 right side


The Casio MX-101 is a MSX1 with a Z80A from Rohm (BU18400A-PS). The MSX Engine is an HD62003 from Hitachi.

The pins SW1, SW2, -12V and +12V of the cartridge connector are not connected. In general, MSXs without a protection switch have pins SW1 and SW2 connected to GND. A few rare cartridges use SW1 and SW2 as GND and some cartridges need the -/+12V as for example the FM-PAC.

The AC power adaptor ouput is 7V with minus at center, 800mA. It is not useful with the expansion unit.

Slot Map without KB-10

Slot 0 Slot 1 Slot 2 Slot 3
Page C000h~FFFFh RAM Cartridge
Page 8000h~BFFFh
Page 4000h~7FFFh Main-ROM
Page 0000h~3FFFh

Slot Map with KB-10

Slot 0 Slot 1 Slot 2 Slot 3
Page C000h~FFFFh RAM Cartridge
Page 8000h~BFFFh
Page 4000h~7FFFh Main-ROM
Page 0000h~3FFFh


  • RF output
  • Analog sound output (mono)
  • Composite video output
  • "UHF channel" connector for antenna (Wireless video signal)
  • MT/IF connector (requires CMT I/F package FA-32 as adapter to use a standard tape recorder)
  • Centronics compatible Parallel port for a printer (on the left side of the KB-10 expansion)
  • 2 general connectors (Joysticks, Mice, Paddle controllers, etc)
  • 1 cartridge slot (without KB-10) or 3 cartridge slots (with KB-10)
  • 1 expansion bus slot for KB-10 unit
  • AC power adaptor connector