What exactly is a gateway?

[monipro]

What exactly is a gateway? Can you describe me what a gateway does? Then what is the difference with a 3rd party processor?
Do you know a good link where I can read about ecommerce, in general I am looking for a Glossary.
Thanks!

[Corey Bryant]

An electronic payment gateway is basically the virtual connectivity between your website & the authorizing agency (First Data, Visanet, Discover, AmEx, etc). Think of it as similar to the POS terminal in the grocery store.

To use an electronic payment gateway (LinkPoint, Verisign, Authorizenet.com) - you will also need to have a merchant account as well.

A third party processor (something like 2CO, Paypal, etc) allows you to use their merchant account to accept credit cards. Normally, when you are using a third party processor, you will be directed over to their site to finalize payment.

With a merchant account & an electronic payment gateway, you can accept credit cards on your secure website

-Corey

[monipro]

Thank you Corey,
now it is all clear.
I wonder why a gateway like authorize.net does not have exact taxes, I couldn't see such anywhere on their site. In another site, listing authorize.net it says "upon agreement". Is it normal for gateways to have different prices.