ZX Spectrum Expansion Systems (Part 2) | Mister Spectrum
... and 24 bits of parallel I/O via an 8255.The BASIC ROM is switched out and replaced by the Forth ROM. Features a Z80 <strong>assembler</strong> for machine code FORTH definitions; a built-in terminal to support a modem and allow access to bulletin-board systems; a machine code monitor which can operate in any number base; RS232 and Centronics printer ...