PJ> payment. But I was asked to find out how does the provider of the service
 PJ> know if the credit card details are correct and also if there is actually
 PJ> the credit on the card ??

I don't know how the on-line services are structured. However, when you
take a credit card order for goods by telephone, you put the caller on hold
after he's given his details, and you call an authorization center. You
quote your merchant number (issued to you by the credit company), the card
number, expiry date, PIN (for Amex), and the amount. You then either get
told "tell him to FOAD", or you are given an "authorization
number". That authorization number is what turns the phone order into
cash.

I believe Visanet etc. now issue the electronic validation equipment
(modem-based dedicated terminal) as standard, and that's even faster.

-- Lewin A.R.W. Edwards [Team OS/2]  Tel 0419320415 * 0412809805 * 0414927056

--- GoldED 2.41+