In an exemplary embodiment, a portable data device is insertable into a docking receptacle for communication with other devices. In route delivery operations and the like, a hand-held computerized data terminal is coupled with a docking unit for recharging of its batteries and communication e.g. with a printer. Preferably, the terminal can be loaded into the docking receptacle with a single motion. The terminal may be automatically positively locked in the receptacle as it is loaded with one hand; thus the terminal may be securely held in the receptacle of a portable printer even if the printer is dropped or subjected to a severe jolt. Removal may be accomplished by a push button-eject or by a single motion with one hand. The disclosure includes various docking configurations which may have non-critical alignment requirements, provide electrical contacts sealed against moisture, and economically accommodate different size terminals and the like. Programmed control of the printer-terminal system provides for feedback from the printer to a primary controller to confirm that each line of data has been actually printed.