It displays and allows editing the codes, reduces retyping and enables easy formatting changes. T.140 allows real-time editing of text e.g. by using 'backspace' and retyping. He was forced to spend much of his honeymoon in Philadelphia retyping the manuscript. This to support overseeing completeness of a number when comparing or retyping. It sealed up the stencil ready for retyping but did not attempt to color match.