Instruction manual

35
Appendix 3 Serial Cables
DO NOT use commercial telephone cables and extensions. In telephone service, the practice is to flip the wires
from end to end. Thus, if you connect multiple cables together, you will not preserve which wire is carrying which
signal. You can check this by holding the two ends of a cable next to each other, oriented the same way (thumb tab
down). If you see that the colors are reversed, you cannot use that cable. You can, however, make your own correct
cable if you like (or get them from us).
Although most of these wires are provided as precut 6-conductor telephone type flat cables (with RJ11 modular
plugs), you may want to cut and install plugs on your own telephone cables. Measure the length needed, and trim
the ends clean. You will need a good quality crimper (available from us or from an electronics supplier such as
Radio Shack).
To install a RJ11 connector, follow these steps:
• Provide good light! If you cannot easily see the smallest details of this task, you will make mistakes and will
not be aware of them. A little extra care in making the connections saves hours of troubleshooting later!
• Use sharp diagonal cutters to trim the end of the cable squarely. You must not have any metal wire strands
sticking out the end.
• Place the cable into the stripping portion of the crimp tool (this has an upper and lower knife to cut the
insulation.
• Pull the cable away, thus stripping about 5/16 in. of the OUTER insulation (the insulation on each wire should
remain).
• Orient the cable in your left hand with the black/white conductors toward the right (Depending on the cable
type, the black may be second from the right). Orient the connector so that the finger latch is DOWN
(underneath). Insert the cable end into the connector until the wires bump the end inside (this is important
because some conductors may in time work their way out of their insulation--leaving space at the end of the
conductor may then allow them to short together).
• Insert the connector with wire into the crimp portion of the tool. Squeeze the handle and check that the six
crimp bars are pressing on the crimp conductors of the connector. Complete the crimp, squeezing hard and
firm.
• Remove the connector. Using a magnifier if necessary, inspect the connector closely and check that all six of
the crimp conductors were pressed down, and that the wire orientation (black to the right with thumb key
underneath) is correct.
Note: the wire orientation in the connector is absolutely critical. Contrary to telephone service, the orientation of
wiring in this system must be maintained. This is so a signal will always travel on the same color wire through the
various connectors and cables.
If the connector is not right in any way, simply cut it off and apply another one. It is virtually impossible to verify
that a particular connector is good or bad: If a cable is suspected as bad, cut off both ends and install new
connectors. If this does not solve the problem, make a new cable.