Baltimore, Md. For every social security account number issued an "employee master card" is made in the Social Security board records office. Testifying data, given on the application blank, form ss-5 is transferred to this master card in the form of up ended quadrangular holes, punched by key punch machines, which have a keyboard like a typewriter. Each key struck by an operator causes a hole to be punched in the card. The position of a hole determines the letter or number other machines will reproduce from the master card. The position of the hole determines the letter or number other machines will reproduce from the master card. From this master card is made an actuarial card, to be used later for statistical purposes. The master card also is used in other machines which sort them numerically, according to account numbers, alphabetically according to the name code, translate the holes into numbers and letters, and print the data on individual ledger sheets, indexes, registry of accounts and other uses. The photograph above shows a records office worker punching master cards on a key punch machine
