its more than you think, but the posts are close....point of sale... is in simple terms, a suit of programs, that does to a point interact with other programs, behind the seens like wal-mart for example... starting with you... you buying a product, point of sale takes that product code, and reduces the inventory count, the inventory count changes the ordering count that goes to the distrabution center, that basicaly does the same thing there, that report goes to the head office then to the buying personal, so they know what to keep in stock, what to let go as discontinued product ( cause it isn't bringing in a quota for sales), each store has at least 2 servers, 1 for instore( LAN: local area network) and one for WAN: Wide area Network, the WAN can talk to all the other stores and to the head offices on encripted land line or satalites. ok... so you go in and buy something, the regester takes what you buy and its retail cost taxes and transactions and sends it to the LAN server the lan server to WAN to head office, then back down to regester, when you swipe your card the card reader sends the info to the regester then back into the LAN and WAN, the head office then takes that transaction to another server, we will call it the banker, that banker looks at the info, calles up you bank, has an exchange and handshake before you info is passes( all networks regardless what kind has this handshake & exchange)once the info is recieved it goes back into the main servers at head office, charted as sale ( retail + tax ( splits tax and stored in another location) retail - cost = proffit) back to WAN then LAN then register to conferm your transaction. every business uses sometype of this layout, maybe not as big, but even in a small store, it still uses point of sale for ordering inventory, whats in inventory, and still has a chatt with your bank, ever notice employees walking around the store with the little scanners??? they are a portable "Node" that talks to the LAN server, they are scanning for price changes, whats in inventory and on shelf stock, the bigger people once or twice a year have a specialty team come in and literly count every item on every shelf, collect that data and transmits that to the head office directly, they take that info, and say look, we sent the store 500 of this item, but they only sold 250 of them, they should have 250 left but the count given is 225, there are no reports of store use( a right off of a product used in the store)no returns ( yes all thats added in to it all) so that means that 25 of the items were taken without payment ( theft) theft is subtracted from proffit, proffets pays the bills, paychecks and whatnot,,, each big store must maintain an account for payroll, store use, and its own bills, so lets say that comes to 45,000-100,000 a month, that store is required to sale at least 20% above that, or get cut offs to compensate the anual % of projected sales and proffits. so, point of sale is the very heart of any business, it is a string of many programs that constantly is split up to do a job then get back with return information and conformation, all in the atempt of under 30 seconds.... don't let others tell you its simple, cause it is far from it, there is constant talking on whatever network used, the little programs that make up "point of sale" is doin it double time,,, by the way... did Ive worked on these systems in the past?? or that I have one of my own??? ooppss sorry... hope this sheds light on you question.