Codings, Slips, Defences, and Repairs

Emphasis on transcription and on avoiding errors and sometimes repairing them

A coding is a transcription. Instead of a postal area spelled out in words, we can use a zip code or a postal code. Our interest is in transcription errors: what happens when somebody writes down the wrong code, for example? Discovering that there has been error is only half the story: what happens next? how easy is it to guess what was intended and fix it – the repair length? We shall look at three coding schemes which have different degrees of defence against slips.