The Atari XTM201 was an 80 column thermal printer designed by Atari Corp for the Atari XE line of computer systems.   The unit is ultra-compact, light and simple to use.   It runs off a 6V 600ma power supply.    The printer accepted either Black & White or Color thermal cartridges.    An interesting note, even though its designation XTM (XE Thermal Monocrome) meant that it was a black and white printer.   If a color cartridge was installed and the self-test is run, it will print out bars of color.
 

        Another more interesting feature of the XTM201 (and also the STC504) is the interfacing system.   Atari corp designed the printers so that they could accept various interface modules such as Atari SIO, Parallel and Serial.   These modules snapped into and out of the back of the printers and connected via a short ribbon cable protruding from the back section of the interface opening.   An Atari XTC201 was mentioned in Atari Corp's 1985 XE Line flyer, but no known proto's of that particular model have surfaced as of yet.