Abstract: The paper tape roll, utilized for providing a printed customer receipt, is disposed in a trough like tray housed behind a drop-down door hinged in the front wall (i.e. the surface facing the machine operator during normal use of a business machine such as a cash register or the like). The path of tape feed progresses from the roll vertically up into a paper feed mechanism arranged in clear view of and for easy access by the machine operator while the operator remains in normal machine use position. The paper tape is then guided by the paper feed mechanism through a receipt printer, below a cutting blade, and out through a window, also provided in the drop-down door, for ready extraction by the machine operator and subsequent delivery to the customer.

Abstract: A device is provided for the exact automatic computation of sales tax rather than calculation of tax as a percentage. In the disclosure, a first subset of tax cutoff values and a second subset of repeating increments of values, corresponding to repeating increments of tax, are stored in a memory. The amount on which the tax is to be calculated is entered into a register and compared in a CPU to the total vlaue of the first subset. The CPU provides a zero output to a register when the amount is less than the first subset. When the amount is larger, the CPU subtracts the first subset from the amount. A divider in the CPU divides the remainder by the total value of the second subset. A multiplier multiplies the whole number quotient, of the division, by a tax amount. The resultant is entered into a register.

Abstract: Correct data stored in an overlay memory register is furnished to a processor, instead of incorrect data stored in a fixed memory register addressed by the processor, by providing a mapping memory that is addressed simultaneously with the addressing of the overlay memory and the fixed memory. The mapping memory is connected with the overlay memory and the fixed memory such that the state of the addressed mapping memory register will enable either the fixed memory or the overlay memory to carry out a data transfer to the processor. The states of the mapping memory registers are preselected in accordance with knowledge of which of the fixed memory registers contains incorrect data.