[4] The case was a little taller than the original Spectrum and the keyboard placement was equal to the original keyboard, except for some additional Sinclair BASIC commands that did not exist in the Spectrums (UDG for user defined characters in the place of the £ sign - including specific Portuguese and Spanish characters such as ç and ñ, as well as accented vowels - and the Trace function).

An improvement over the original ZX Spectrum was the sound output via modulated RF direct to the TV set instead of the internal beeper.

[10] It was successful in other Latin American countries, such as Uruguay and Argentina, as an export model using a different circuit board and schematics, and the same Ferranti ULA as the ZX Spectrum.

Because of its affordability in Latin America, many commercial software programs were developed locally for small business use and millions of users had their first computer experience with the TK90.

There's an active user base of enthusiasts of this computer, with dedicated websites discussing software preservation, peripherals and homebrew development and modifications.