Brother HL-7050 Series User Manual page 83

When you use the Automatic Interface Selection, note the
following:
This function takes a few seconds to work. If you want to
speed up printing, select the required interface manually in
the SELECT menu by using the control panel in the
INTERFACE menu.
If you constantly use only one interface, we recommend that you
select that interface as the default setting in the INTERFACE menu.
The printer allocates the entire input buffer to that interface when
only one interface is selected.
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