Since Sphere is a Software-as-a-Service (SaaS) based application, there is not a method to being able to interface a credit card machine or Point of Sale machine to Sphere for automatic transfer of donation or registration information.

An alternative solution would be to create a spreadsheet of all the registrations and/or donations received outside of Sphere for an event, and you can then use the Batch Entry System to import them all at the same time.