|Language||Sinclair Basic (128K and 48K)|
|CPU||Zilog Z80 A|
|ROM||32KB (16KB BASIC for each model 48K and 128K)|
|Colors||8 (*2 tones)|
|Sound||Yamaha AY-3-8912: 3 channels, 7 octaves|
|IO||Expansion bus, numeric keypad, RS232 (and MIDI), RGB, tape|
In 1985, Sinclair developed the ZX Spectrum 128 (code-named Derby) in conjunction with their Spanish distributor Investrónica (a subsidiary of El Corte Inglés department store group). Investrónica had helped adapt the ZX Spectrum+ to the Spanish market after the Spanish government introduced a special tax on all computers with 64 KB RAM or less, and a law which obliged all computers sold in Spain to support the Spanish alphabet and show messages in Spanish.
The appearance of the ZX Spectrum 128 was similar to the ZX Spectrum+, with the exception of a large external heatsink for the internal 7805 voltage regulator added to the right hand end of the case, replacing the internal heatsink in previous versions. This external heatsink led to the system's nickname, "The Toast Rack".
New features included 128 KB RAM with RAM disc commands 'save !"name"', three-channel audio via the AY-3-8912 chip, MIDI compatibility, an RS-232 serial port, an RGB monitor port, 32 KB of ROM including an improved BASIC editor, and an external keypad.