The TK90X was a Brazilian ZX Spectrum clone made in 1985 by Microdigital Electrônica, a company from São Paulo, that had previously manufactured ZX80 (TK80, TK82) and ZX81 clones (TK82C, TK83 and TK85). Reported TK90X sales in October 1986 were 2500 machines per month. Technical details The case was a little taller than the original Spectrum and the keyboard placement was equal to the original keyboard, except for some additional Sinclar 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 and , as well as accented vowels - and the Trace function). There were two versions of the machine, with 16 KB and 48 KB of RAM. They contained the same Z80A processor running at 3.58 MHz, a ROM chip, and RAM chips (dynamic RAMs 4116 and 4416). Microdigital reverse engineered a CMOS integrated circuit (IC) with similar functionality to the original Bipolar IC ULA from Sinclair/Ferranti. The TV modulator was tuned to VHF channel 3, with the TV standard being hardware selectable to PAL-M (60 Hz) as used in Brazil, PAL-N (50 Hz) as used in Uruguay, Argentina and Paraguay and NTSC (60 Hz) as used in USA and many other countries. An improvement over the original ZX Spectrum was the sound output via modulated RF direct to the TV set instead of the beeper. Most software written for the Spectrum ran on the TK90X, with some minor incompatibilities. Only three peripherals were released by Microdigital — a Joystick, a light pen interface and a parallel printer interface. A Beta disc (48) interface was made by third party companies, called 'C.A.S. disk drive interface' (a near-clone from the original Beta disc interface), 'C.B.I. disk drive interface' (with a printer interface included) and 'IDS91' (with a printer interface included made by Synchron) or 'IDS2001ne' (these exclusively compatible only with the TK90X or TK95 {no ZX Spectrum use possible}, also from Synchron, and also with a printer interface included). TK95 The TK90X was replaced by the TK95, which had a different keyboard (professional) and case (identical to the Commodore Plus4) and exactly the same circuit board and schematics. The motherboard was marked as TK90X. The unit had a few differences in the ROM that made the TK95 more compatible with the original ZX Spectrum. It used the same ULA chip,