Panasonic KX-FP121 Operating Instruction page 69

Receiving
Faxes
Using the
unit
and
a
computer on
the
same
line
===
We
recommend you use separate
wall
jacks
for
the unit
and
the
computer.
Note:
•
Set
the
TEL mode
on the fax
machine.
• The
device
which has the shortest
ring
count
will
answer a
call
first.
Confirm
the ring
count
for
each
device.
69