AIDC stands for Automatic Identification and Data Capture. It is one of the most prevalent technologies on the planet. It is so prevalent, in fact, that you don't even realize you're using it a half dozen times a day.
Specifically, AIDC is the collection of data into a device for identification and validation purposes without the use of a keyboard. Examples of this kind of functionality are everywhere. Any time you swipe your credit card, you are allowing the swipe device to perform AIDC on your card. Remember that the next time you use your credit card to buy gasoline, groceries, coffee, or any other of a huge handful of things that can be bought with credit these days. These cards have magnetic strips which contain user information that can be accessed via the swipe.
Speaking of groceries and coffee, one technology that is all the rage these days is the smart card. This card can be "loaded" with a certain amount of money. Each time you swipe the card, the swipe device's computer subtracts from your card's balance the amount due for the transaction at hand. When your balance reaches 0, it's time to "reload." Coffee stores, grocery stores, and other kinds of retail outfits offer this kind of smart card to their customers.
AIDC isn't just for credit cards or smart cards that have magnetic strips, either. Many companies issue employee name tags or ID cards that contain magnetic strips which enable the employees to enter or exit the building's security system. The information contained on such ID cards is usually only the name of the employee, but it can also include more personal information.
You might also have a card that is specific to a place that you shop. Many grocery stores and book stores have their own cards, which give the bearers related discounts just for being "members." Like employee ID cards, these cards use AIDC to identify the user and calculate the appropriate "member discount" for select items.
Another example of AIDC is bar codes. Most foods nowadays come with stickers attached. These stickers have UPC codes, bar codes, or both. A scanner at the grocery store checkout counter accesses the information stored on the bar code of each item of food and then processes that information into setting a price.
If the grocery store has done its homework, then each bar code scan will result in a corresponding price. It's not just used in grocery stores, either. Most retailers nowadays put bar-code tags on their inventory and use bar-code scanners to ring up prices at checkout.
One example of AIDC that is all the rage in certain circles these days is the RFID tag. RFID, or Radio Frequency Identification, tags are the next generation of bar codes. Rather than a static bar code signal, however, an RFID tag contains a radio frequency that can, like a bar code, be read with a special kind of reader. RFID tags are becoming more and more prevalent in modern society. One particularly timely example is that of a Chinese company using the tags to track chickens and other birds that are prone to avian flu. A specific debate has arisen over using the tags to identify people through AIDC.