This is a switch that allows the phone line to be either
connected to the fax machine or to be bypassed, so the
desk phone will work normally without problems. Of
course, a somewhat neat installation was highly desirable.
The necessary components were purchased at a
nearby home supply store and at a local
electronics supply company for the switch
itself. They can also all be easily obtained
on the Internet (Photo 1).
The two-port surface box holds two
modular RJ- 25 phone connectors which
provide connection points for the phone
line and desktop telephone, and has a nice
appearance. It came with double-sided
adhesive pads which made it simple to
attach it to the base of my printer for easy
The 25 foot phone cord — with
connectors — was cut to provide the two
cables that run to the fax connections on
my printer. The remainder of the wire went
to the scrap box for another project.
The first step was to do a quick mock-up to confirm the needed clearances when
the parts were assembled (Photo 2).
This confirmed that there was
sufficient room for the wiring, so it was “all
The original wiring diagram was done quickly on a
scrap of paper, but Figure 1 is a neater version made with
CAD. It also includes base diagrams of the jacks and
switch, but confirm that yours will match before wiring.
Several holes are needed in the plastic cover for
mounting the switch and for the cables to the fax machine
to pass through. By using hard wired cables for the
connections to the fax machine instead of two more jacks,
much space is saved and the overall device is kept smaller.
Plus, the cost of two jacks and two connectors is saved.
In Photo 3, the locations for these holes have been
carefully determined and laid out on Scotch Magic Tape™
December 2015 29
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■ Photo 1. The parts.
■ FIGURE 1.
■ Photo 2. Mock-up.