Memory was in the form of 13-bit "syllables", each with a 14th parity bit.
A parity bit tells whether a group of bits is even or odd.
None means that no parity bit is sent at all.
The parity bit is an example of a single-error-detecting code.
Bit 8 is the even parity bit of bits 0-7.
If a parity bit is used, it would be placed after all of the data bits.
If all parity bits are correct, there is no error.
In retrospect a solution could have been to add a parity bit to each number as written.
If the total number of 1s is odd, the parity bit is set to 1.
If the total is even, the parity bit is set to 0.
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