Memotech RS128

The Memotech RS128 extended the MTX family to 128KB of main memory while retaining its Z80 processor, aluminium case and Texas Instruments graphics and sound hardware. It was intended for more demanding communications, disk and business applications.

The additional bank-switched memory complemented Memotech's RS-232 communications and FDX or HDX storage options. Produced in far smaller numbers than the MTX500 and MTX512, the RS128 is one of the rarest commercial members of the range.

Notable Features

• 128KB of bank-switched RAM provided substantially more capacity than the MTX512.
• Designed to make fuller use of Memotech's communications and disk expansions.
• Retained compatibility with the established MTX graphics, sound and BASIC environment.

Historical Significance

• Represented Memotech's move from the home-computer market toward communications and small-business systems.
• Its limited production reflects the company's worsening commercial position during 1984.

Collector’s Notes

• RS128 machines are scarce and can be confused with upgraded MTX512 systems.
• Internal board markings and memory configuration provide stronger identification than the shared case alone.

Specifications

Technical Information
Name	Memotech RS128
Manufacturer	Memotech
Launched	Sunday, January 1, 1984
Launch Price	£399
Country	United Kingdom
CPU	Zilog Z80A at 4 MHz
Units Sold
Operating System	MTX BASIC and monitor; CP/M with suitable disk hardware
I/O	RF, composite video, audio, joystick, Centronics, cassette, cartridge, expansion and optional RS-232
Keyboard	Integrated full-travel mechanical keyboard with numeric keypad
Storage	Cassette; optional FDX floppy and HDX hard-disk systems
Sound	SN76489A, three tone channels plus noise
Graphics	TMS9929A, 256 x 192 pixels, 16 colours and 32 sprites
Display	40 x 24 text; optional 80-column display with disk systems
ROM	24KB containing MTX BASIC, monitor and utilities
RAM	128KB bank-switched main RAM plus 16KB video RAM
CPU Speed	4 MHz