Brother MFC-640CW - Manual (Page 185)

APPENDIX A A - 12
Special line considerations
Roll over phone lines
A roll over phone system is a group of two or more separate
telephone lines that pass incoming calls to each other if they are
busy. The calls are usually passed down or “rolled over” to the next
available phone line in a preset order.
Your machine can work in a roll over system as long as it is the last
number in the sequence, so the call cannot roll away. Do not put the
machine on any of the other numbers; when the other lines are busy
and a second fax call is received, the fax call would be transferred to
a line that does not have a fax machine. Your machine will work
best on a dedicated line.
Two-line phone system
A two-line phone system is nothing more than two separate phone
numbers on the same wall outlet. The two phone numbers can be on
separate jacks (RJ11) or combined into one jack (RJ14). Your
machine must be plugged into an RJ11 jack. RJ11 and RJ14 jacks
may be equal in size and appearance and both may contain four
wires (black, red, green, yellow). To test the type of jack, plug in a
two-line phone and see if it can access both lines. If it can, you must
separate the line for your machine. (See on page 4-6.)
Converting telephone wall outlets
There are three ways to convert to an RJ11 jack. The first two ways
may require assistance from the telephone company. You can
change the wall outlets from one RJ14 jack to two RJ11 jacks. Or,
you can have an RJ11 wall outlet installed and slave or jump one of
the phone numbers to it.
The third way is the easiest: Buy a triplex adapter. You can plug a triplex
adapter into an RJ14 outlet. It separates the wires into two separate
RJ11 jacks (Line 1, Line 2) and a third RJ14 jack (Lines 1 and 2). If your
machine is on Line 1, plug the machine into L1 of the triplex adapter. If
your machine is on Line 2, plug it into L2 of the triple adapter.
RJ14
RJ11
Triplex Adapter
RJ14