If you have a keyboard wedge (which you probably do), then the computer sees no difference between characters entered by scanning the barcode and characters entered by typing. Scanning data and performing an XLookup OnElementChange or OnElementExit should not be a problem.

You should be able to use the SelectTreeItem commands or macros to retrieve a customer record, but exactly how it works depends on the specifics of what you are trying to do.

I don't see subforms being an appropriate solution for either of the tasks you describe, although subforms would be appropriate for multiple line items on an Invoice.

Steve,

Are your items for sale unique? Is each rug an individually identifiable item, or do you carry 50 of the exact same rug?

Does each invoice represent the sale of a single item, or can you sell 5 rugs to the same person on the same invoice?

Hi Steve,

I can't really perform on-the-fly application design with such a limited knowledge of your needs, but I'd head in a direction like this:

PointOfSale Application
--- Customers database and Form, where each record represents one Customer
--- Inventory database and Form, where each record represents one unique item for sale
--- Invoices database and Form
------ Line Items database and Form (used as naturally linked subform on Invoices Form) 

Invoices should include the CustomerID, which can use XLookups to fill in address info. LineItems should include the InventoryItemID (from your barcode), which can use XLookups to fill price, description, etc.

To get a Purchase History for a Customer, search the Invoices database or run a Report. To find who bought a particular item, again, search the Invoices database for that item number. By searching in a subform, you will find any parent (invoice) record under which that item appears.

I hope this helps to get you started.