This is the back of the Atom. From left to right we have the Acorn Bus Extension, VIA Printer I/O, Video, DC In, Tape and UHF.

The Acorn Bus Extension and printer interface were optional upgrades not fitted to basic Atoms.

You can see here that both the printer and video ports have wires coming out of them. This is not normal and indicates that somebody has been tinkering about with the insides of the Atom.