Brother MFC-420CN - Manual (Page 54)

3 - 8 SETUP SEND
Dual Access (Not available for color faxes)
You can dial a number, and begin scanning the fax into memory—
even when the MFC is sending from memory or receiving faxes. The
LCD shows the new job number and available memory.
Your MFC normally uses Dual Access. However, to send a color
fax, the MFC will send the document in real time (even if
Real
Time TX is Off ).
The number of pages you can scan into the memory will vary
depending on the data that is printed on them.
If you get an Out of Memory message while scanning the first
page of a fax, press Stop/Exit to cancel scanning. If you get an
Out of Memory message while scanning a subsequent page,
you can press Black Start to send the pages scanned so far,
or press Stop/Exit to cancel the operation.