Electronic cash register system

An electronic cash register system having a plurality of electronic cash registers which are connected to a common data bus so as to transmit data from one cash register to another and assignable to a plurality of operators given respective operator codes,

• at least one of said cash registers comprising a first storage means for storing customer numbers and the data relating to merchandise sold and corresponding to the respective customer numbers for each of the operator codes, and a second storage means for storing tip amount data corresponding to the respective operator,
• each of said cash registers further comprising:
• (a) mode setting means for setting the cash register into a registration mode or a liquidation mode,
• (b) input means for entering data into the cash register, and having tip entry means including a tip designation key,
• said tip entry means being operative on setting the cash register to the liquidation mode and further on entry of said particular customer number and depression of said tip designation key to read out the operator code corresponding to said particular customer number from said first storage means and cause said second storage means corresponding to said read-out operator code to store tip amount data entered through said input means,
• (c) means operative on setting of the cash register to the registration mode and further on entry of an operator code, a customer number and data relating to merchandise sold through said input means to cause said first storage means corresponding to the operator code so entered to store said entered customer number and data relating to merchandise, and
• (d) means operative on setting of the cash register to the liquidation mode and further on entry of a particular customer number which has been stored in said first storage means to read out the data relating to merchandise corresponding to said particular customer number from said storage means so as to perform a liquidation transaction.