On 26-Feb-12 10:10, Roland Perry wrote:
In message , at 15:39:25 on Sun, 26 Feb
2012, Adam H. Kerman remarked:
My one step: Enter PIN which is checked, and terminal asks CCC
for auth for the exact amount, checking for stolen
cards, floor limits and available credit.
Their one step: [Usually] CCC sends auth to retailer's terminal, which
displays "accepted".

Does the retailer also receive a transaction ID number, a number that
also appears on the cardholder's monthly statement?

If so, then the procedure is comparable to what happens here.

UK credit card statements (including Amex) don't usually have
transaction numbers.

Nor do any of my current US credit, debit or charge card statements. I
vaguely recall one bank including transaction numbers a decade or two
ago, but not since then.

What I was disputing was your retailer "two pass model", with the card
itself being authorised up to some "reserved" amount, ahead of the
actual amount being claimed milliseconds later by the retailer. I don't
know why they'd do that, rather than ask for authorisation of the actual
amount first, because in the UK the amount has to be known before you
enter your PIN into the C&P device, as entering your PIN is an agreement
to pay that precise amount.

The two-pass scheme is used in other circumstances, such as checking
into a hotel, when they often "reserve" an estimate of the final bill,
ahead of the day you eventually check out.

Hotels are the most obvious example, but restaurants with waitstaff do
the same thing: they will authorize the card for the subtotal (price
plus tax) plus a liberal estimated tip (eg. 20-25%). Either way, the
actual total isn't submitted until the transaction is
posted--potentially several days, not "milliseconds", later.

Most other merchants authorize for the exact total, since it is known as
soon as the purchases are rung up. The main exception is when the
transaction is below the merchant's "floor", in which case they aren't
required to authorize at all: they just post the transaction when they
get around to it--and if posting fails, the card processor eats the loss.

S

--
Stephen Sprunk "God does not play dice." --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSS dice at every possible opportunity." --Stephen Hawking