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Forth Cartridges
Forth cartridges provided a way to run Forth programming
environments on the Sinclair ZX Spectrum, sometimes with
additional hardware interfaces and machine-code development
facilities. This section documents known Forth cartridges,
their technical features, contemporary descriptions and
published prices where these can be established from
surviving sources.
Features
Original Price
Currah µSource
Currah
Description not yet available.
Price not yet available.
Spectrum Forth IO Cartridge
Skywave Software
The Skywave Software Spectrum Forth I/O Cartridge contains 12K of fig-FORTH and provides an RS-232 serial interface using an Intel 8251 and 24 bits of parallel I/O using an Intel 8255. It replaces the Spectrum's BASIC ROM with its Forth ROM, which contains the standard fig-FORTH words alongside additional facilities.1
Features include a Z80 assembler for machine-code Forth definitions; a built-in terminal for modem communications and access to bulletin-board systems; and a machine-code monitor supporting different number bases, simple one-line assembly and disassembly. RS-232 and Centronics printer routines can be used from either Forth or BASIC. The cartridge also supports RAM-disc simulation and Microdrives, and provides access to the Spectrum's colour, sound and graphics facilities from Forth.1
The cartridge is built on a PTH printed circuit board and has a standard DB25 connector for serial I/O and a strip-cable connector for parallel I/O. It is suitable for both 16K and 48K versions of the ZX Spectrum and was supplied with an extensive manual.1
Features include a Z80 assembler for machine-code Forth definitions; a built-in terminal for modem communications and access to bulletin-board systems; and a machine-code monitor supporting different number bases, simple one-line assembly and disassembly. RS-232 and Centronics printer routines can be used from either Forth or BASIC. The cartridge also supports RAM-disc simulation and Microdrives, and provides access to the Spectrum's colour, sound and graphics facilities from Forth.1
The cartridge is built on a PTH printed circuit board and has a standard DB25 connector for serial I/O and a strip-cable connector for parallel I/O. It is suitable for both 16K and 48K versions of the ZX Spectrum and was supplied with an extensive manual.1
Skywave Forth IO Cartridge
Price not yet available.
References
1.
"Going FORTH" - Describes the Skywave Software Spectrum Forth I/O Cartridge, detailing its fig-FORTH ROM, RS-232 and parallel I/O interfaces, programming tools, printer routines, Microdrive support and compatibility with 16K and 48K ZX Spectrum models., ZX Computing, No. October/November 1983, p. 61
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External Links
Checking the Currah microsource (U-Source)
(Youtube / Davide Barlotti)
Page Revised: 25/10/2026