modes: Standard ZX Spectrum mode (256x192, 2 colors per block of 8x8 pixels from 16 colors), EGA-like mode 320x200, 16 colors per pixel; 640x200 high resolution mode, 2 out of 16 colors per 8x1 pixels Color palette : 64 colors, 16 can be used at the same time Firmware: BASIC48 / 128; TR-DOS; CP/M 2.2 Supported external drives: tape recorder; drive Sound devices: standard 1-bit bepper; AY-3-8910; Covox Additional devices: SECAM encoder for connection to color TV; Single-channel DAC; Modem; Centronics interface for connecting a printer; Stereo audio amplifier 2x1W Keyboard : mechanical matrix, standard for ZX Spectrum (40 keys, or extended, 64 keys) ATM Turbo 2 (1993) New features (relative to ATM Turbo 1): Memory manager: the ability to include any page of RAM or ROM in any of the quarters of the address space Text mode: 80x25 text video mode, characters are stored in the character generator ROM. It is possible to set any of 16 colors for the symbol and background Hardware vertical scrolling in EGA and 640x200 modes Supported external drives: controller for IDE devices (hard drives of any capacity, CD-ROM ); Digital PLL added to floppy controller Additional devices: eight-channel DAC Keyboard: XT keyboard support, on-chip RAM 537RU10 Removed the following devices: SECAM encoder ATM Turbo 2+ New features (comparing to ATM Turbo 2): RAM: 128 to 1024 KB Additional devices: RS-232 interface; Channel switch for DAC Keyboard: support for XT and AT keyboards, based on the 1816BE31 (i8031) microcontroller Removed the following devices: Modem The xBIOS ROM has been specially developed for ATM Turbo 2+ with support for virtual floppies. Also for ATM Turbo 2 (+) there is a ROM version of Mr Gluk Reset Service. ZX Evolution New features (comparing to ATM Turbo 2+): Turbo mode up to 14 MHz, switchable via menu and software 4MB RAM: both ATM Turbo 2 (+) and Pentagon 1024 Expanded Memory Supported 2 expansion slots according to the ZXBUS standard for connecting General Sound, etc. Flexible architecture based on FPGA (EP1K50) - third-party firmware available SD card with transparent BIOS support (EVO RESET SERVICE) Added VGA video output Non-volatile clock according to Mr Gluk standard, IDE interface according to Nemo standard, mouse according to Kempston Mouse standard Video scan rate from the Pentagon computer, with full support of all border and multicolor effects References Computer-related introductions in 1991 ZX Spectrum clones Soviet computer systems