Any barcode scannter that you can connect to the computer that runs in "keyboard emulation mode"--the default setting on nearly any bar code scanner can be used pretty simply with any version of FileMaker. The computer thinks the scanner is another keyboard hooked up to the computer and the scanned barcode is entered as plain text into whatever field has the focus at the time that you scan the bar code.
If you can configure the scanner to put additional characters at the beginning and end of the scanned text--many scanners add a return after the last character automatically, you can use that feature to further automate the process:
a) If you can put a "pre-amble" on the scanned text, you can use OnLayoutKeystroke to detect a particular character or set of characters as the signal that a scan has started and use go to field or go to object to put the focus (cursor) into the correct field so that the remaining characters are automatically captured in the field you have set up for that purpose.
b) if you can put a return, enter or tab as the "post-amble", you can use that character along with the inspector's behavior setting on the designated scan field to trip the OnObjectExit or OnObjectSave trigger to perform a script to do any "Post scan processing" that may be needed. And this setting then allows the user to manually enter the same code--say the tag is damaged or the scanner goes down and can press the same key to get the same result--just like you see cashiers manually entering codes at the supermarket.
Most usb barcode scanners use keyboard emulation, so you just click in the field, scan the bar code, and the scanned data is inserted into the field as if it were typed. Most scanners also allow you to configure them to add characters or key commands before or after the scan (e.g.: a tab).
If that's too fragile for your application, then get an RS232 scanner or a USB scanner that emulates a serial port, then use TROI Serial Plugin or similar to interface with it. Then you can run a script to handle the processing of the scanned data.
An other option is, if the barcode scanner adds a return to the code, is to use a looping script and capture
the barcode in a dialog box, the entry with the return shall continue the script which can process the barcode.