The inventor of the ATM,
http://en.wikipedia.org/wiki/John_Shepherd-Barron, at first envisioned a six-digit numeric code for customer
http://en.wikipedia.org/wiki/Authentication. His wife however could only remember four digits, which became the most commonly used length.
http://en.wikipedia.org/wiki/Personal_identification_number#cite_note-milligan-3http://en.wikipedia.org/wiki/ISO_9564-1, the international standard for PIN management and security in retail banking, allows for PINs from four up to twelve digits, but also notes that "For usability reasons, an
http://en.wikipedia.org/wiki/ISO_9564#PIN_selection should not exceed six digits in length."
http://en.wikipedia.org/wiki/Personal_identification_number#cite_note-7 Financial PINs are often four-digit numbers, with
http://en.wikipedia.org/wiki/Switzerland being a notable exception with six-digit
PINs being given by default. Most ATM and POS software does not support PINs longer than six digits, and many input devices can only accept four digit PINs.
I'd like to know why the present progressive form is used in "PINs being given."
Thank you in advance for your help.