Brother MFC-J6510DW Service Manual page 263

(8) In Port on the BrUsbSn screen, select the port number assigned to the Brother
Maintenance USB Printer. If the port number is unknown, follow steps 1) through 4)
below.
1) Click Start | Settings | Printers.
The Printers window appears as shown below.
2) Right-click the Brother Maintenance USB Printer driver icon.
3) Click Properties.
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