Romh,
The easiest way to handle the input of data from barcode scanners is to utilize scanners that plug into into the keyboard port of the PC. In addition, the scanners should be of the type that handles the "decoding" of the barcode data into ASCII characters (the alternative is a "dumb" scanner that requires the use of a "wedge" program on the PC to perform this decoding - not recommended).
To your Access program, the output from the barcode scanner looks exactly like the information has been entered from the keyboard. In a Point of Sale application, the user scans a barcoded price tag, and the program accepts the string of characters from the scanner, looks up the item in it's scan file, and registers the sale. You don't, necessarily, need to do anything special in your program to deal with this. Just write it to properly handle keyboard input of the item numbers (or SKUs) and then have your users use the barcode scanners instead of the keyboard to enter this information.
With regard to interfacing your program to a cash drawer: Most Point of Sale printers include a connection (typically an RJ-11 "telephone" type plug) that connects it to the cash drawer. The printer will accept a command string (found in the printer's documentation) that will in turn cause the cash drawer to open. This command string should be sent to the printer when a cash sale (or a No Sale) is rung up.
Hope this is helpful,
Ted
