The present invention relates to a data transmission interface for transmitting data between a system and an utilization device, such as a printer, and more particularly, to an interface which utilizes the system's power connection to effect the data transmission.
Various data transmission interfaces exist in the prior art for transmitting information from a system unit, such as a computer, to an utilization device, such as a printer. These interfaces include both parallel and serial data transmission and usually consist of a separate dedicated channel over which the information is transmitted. Both the system unit and the printer unit are often powered by differing power sources connected directly thereto. Further, it is known to transmit information over a power distribution system such as that found in a household or office. Such systems are employed in conjunction with microprocessors to control various household devices, such as burglar alarms.
Patient monitor devices are also known which operate to analyze patient samples and provide an output indication of the results of the analysis on a temporary display device. These devices are generally small allowing for portability so that they can be placed near a patient and thus do not incorporate a self-contained mechanism for creating a permanent record such as a printer. An example of such a patient monitor is the Biotrack 512 monitor. This monitor may be disconnected from its power source and operate on battery power while temporarily being located adjacent to patient in order to collect and analyze patient samples. The monitor may then be plugged back into its power source in order to recharge its batteries or perform analysis on patient samples brought to the monitor. It is important that simple connections be established between the monitor and the utilization device in order to prevent setup error as well as to conserve space and thus to make the system readily portable.
While the above summarized prior art is useful in providing data communication between devices, it does not suggest an approach which relies on a simple connection of both power and signal communication facilities between a portable monitor and an utilization device, such as a printer, operating in an environment where communication must be error-free in order to insure accuracy in the communicated data.