The first computer based edit systems typically used punched paper tape to save the EDL information.
The tape was one-inch wide, and each line of the EDL took approximately eight inches of tape.
Remex was the maker of a popular high speed paper tape reader/punch, and also the supplier of blank paper tape. The arrow points towards the start of the tape. Generally the starting end of the tape was also cut in the shape of a point.
The smaller holes near the center of the tape are used to drive the tape through the reader. Each row of the larger holes (top to bottom in the above picture) represent one character in the EDL.
Each row of holes across the tape represent one character in the EDL.
These characters, A-Z, 0-9, and others, are called ASCII characters, and the entire ASCII character set can be represented by a value ranging from 0 to 127.
Each row on the tape has space for eight holes. Each hole represents a binary value. With eight holes, we can represent any number between 0 and 256.
The binary value for the right most hole is 1, the next is 2, the next 4, and so on to the left most hole which would represent 128.
For EDL's, we only need the right most seven holes. The left most hole is the "parity" bit. This bit is used to insure that we have read each row correctly. You'll notice, that all row's have an even number of holes. In reading the tape, we can ignore the left most hole or parity bit.
Here's our cheat sheet: A space is 32 (6th hole from the right), the number 0 is 48 ... and the number 9 is 57. Finally, the colon is 58. Letter A is 65 ... and the letter Z is 90.
In the above example, for reference, the top row shows all holes punched. The second row shows the holes needed for the number three.