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A daisy wheel printer is a 1970s-1980s impact printer, invented in 1969 by David S. Lee, that uses a rotating wheel with molded characters at the end of spokes to produce high-quality, typewriter-like text. A hammer strikes the character against an inked ribbon, making it popular for word processing but slow and loud.

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A chain printer is a high-speed, impact line printer used primarily in the 1950s–1980s, which prints an entire line of text at once (400 to 3000 lines per minute) by moving a character chain horizontally across the paper. Individual hammers behind the paper strike it against an inked ribbon and the revolving character chain, famously utilized in the IBM 1403.

In Computer Studies, the words 𝘤𝘩𝘢𝘪𝘯 and 𝘵𝘳𝘢𝘪𝘯 are often used interchangeably as in Chain/Train Printer.

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ET, here, could mean Extra Terrestrial i.e. the ET 57 PC is – like 𝗧𝗵𝗲 𝗜𝗻𝘁𝗲𝗿𝗼𝗰𝗶𝘁𝗼𝗿 – an example of alien-human hybrid technology.