Device for interfacing point of sale systems with external peripheral units

A device for interfacing an external peripheral unit to a point of sale (POS) system having a store terminal and a store controller, the device including a first connector for coupling to the store terminal and a second connector for coupling to the store controller, the device further including a third connector for coupling to the external peripheral unit, comprising:

• a microprocessor unit (MPU);
• relay means coupled between the first and second connectors and operable in a first state to provide a first data path between said first and second connectors and operable to a second state for selecting interrupting the flow of data therebetween and for establishing data paths between said MPU and each of said first and second connectors for transferring data between said MPU and each of said first and second connectors;
• first means for transferring data between said first connector and said MPU;
• second means for transferring data between said second connector and said MPU;
• third means for transferring data between the third connector and said MPU;
• and wherein said relay means and said first, second and third means are controlled by said MPU, said relay means being selectively switched between said first and second states by said MPU;
• said MPU selectively switch of said relay means in response to predetermined signals at one of said first, second and third connectors.

A method for allowing an external peripheral unit coupled to a first connector to interface with a point of sale (POS) system having a store terminal and a store controller respectively coupled to second and third connectors, the method comprising the steps of:

• passively monitoring data from one of the connectors so as to not interrupt the normal flow of data between the store terminal and the store controller;
• detecting a predetermined data pattern from said one of the connectors indicative of a request to access the external peripheral unit;
• interrupting the normal flow of data between the store terminal and the store controller in response to said detection of said predetermined data pattern;
• providing a plurality of data paths for processing and transferring data between the external peripheral unit, the store terminal and the store controller.