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256 USING SERVO MOTORS

Connector Styles and Wiring

While some servo specifications may vary from one model to another, one thing that’s much
more standardized is the connectors used to plug servos into their receivers.

CONNECTOR TYPE

There are three primary connector types found on R/C servos:

• “J” or Futaba style
• “S” or Hitec/JR style
• “A” or Airtronics style

Servos made by the principal servo manufacturers— Futaba, Airtronics, Hitec, and
JR— employ the connector style popularized by that manufacturer. In addition, servos made
by competing manufacturers are usually available in a variety of connector styles, and connec-
tor adapters are available.

PINOUT
The physical shape of the connector is just one consideration. The wiring of the connectors
(called the pinout) is also critical. Fortunately, all but the “old- style” Airtronics servos (and the
occasional oddball four- wire servo) use the same pinout, as shown in Figure 23- 6.
With very few exceptions, R/C servo connectors use three wires, providing ground, DC
power (+V), and signal. The +V DC power pin is virtu-
ally always in the center; that way, if you manage to
End view
plug the servo in backward, there’s less chance of
J-type (Futaba)
damage. (An exception to this is what’s referred to as
“old- style Airtronics,” a wiring scheme no longer in
S-type (Hitec, JR)
use. You may encounter it if you have some older- model
Airtronics servos.)

Keyway = COLOR CODING
signal terminal
Most servos use color coding to indicate the function
of each connection wire, but the actual colors used for
the wires vary among servo makers. Some of the
1 2 3 more common wire color coding is::

Ground • White, orange, or yellow: Signal
Signal • Red: +V (DC power)
• Black or brown: Ground
+V
USING SNAP- OFF HEADERS
Figure 23- 6 Standard three- pin connector FOR MATED CONNECTORS
used on the vast majority of RC servo motors. The
connector may or may not be “keyed” using a R/C servos and their mating receivers use polarized
groove or notch. connectors to help prevent plugging things in back-

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