Tap Device Management from the Settings page to view the list of available card readers that your device can be connected to.
If you are using a Swift B200 or Swift B250, the four digits represent the last four digits of the card reader’s serial number.
Set Default Devices
To set a default reader, select a reader by tapping on it and tap Set Default Reader on the next page.
To set a default printer, select the printer by tapping on it and tap Set Default Printer.
To print a test receipt select a printer and tap Print Test Receipt.