Data entered at the keyboard of the teletype could be directed
to a perforator or punch which punched a pattern of holes
across the width of a paper tape to represent the characters
typed. The paper tape could be read by a tape reader feeding
the computer. Computer output could be similarly punched onto
tape and printed off-line.
As well as storage of the program and data, use of paper tape
enabled batch processing.
The first units had five data hole positions plus a sprocket hole
(for the driving wheel) across the width of the tape. These used
commercial telegraph code (ITA2 also known as Murray), Baudot
code or proprietary codes such as Elliott which were more
programmer-friendly. Later systems had eight data holes and used