The XBee slave unit just plugs into the RS-232 connector of the ajet 101. The unit is about two inches long; the camera angle makes it seem larger.
Even if you have access to a PC or laptop some customers object to having computer on the factory floor. Many have used a handheld in this case but a handheld terminal (sometimes called a KID) has a small LCD screen and a limited keypad. These limitations can cause difficulties, frustration and errors. With the XBee accessory the user can program an ajet printer using a computer with a full screen and keyboard and the computer doesn’t have to be in the factory.
Finally, and most important, the slave units are addressable so that the master unit and communicate with any number of individual slave units. For example, if you had five slaves they could be numbered 1 thru 5 and if you wanted to program the ajet printer connected to number three then just give the master the command to talk to number 3 and the other slaves would ignore the communication.