How do you tell?
Figure 1 shows a simple test jig that will make it easier
for you to quickly check the continuity of a four-conductor
USB cable. The only parts needed are two (or more)
“breakout” boards with female USB receptacles to match
the ends of the USB cable you want to test and something
to mount them on.
(I used the USB type A, USB Micro-B, and USB Mini-B, and fastened them to a small piece of wood.)
Simply plug in your questionable cable to the
appropriate mating female connectors on the test jig as
shown and use an ohmmeter to check continuity by
probing matching pin numbers on each breakout board.
You can also verify the interconnection of pins 4 and 5 on
an OTG cable (see sidebar).
As an after-thought, I added the simple LED continuity
BUILD IT YOURSELF
If you’re like me, you likely
have a drawer or shoebox
stuffed with assorted USB
cables that are used to
either charge or program a
USB device. The problem
often is that some cables
may only be useful for
charging, and which only
have the +Vcc and ground
wires intact with one or
both data wires either
broken or not connected in
the first place.
BUILD A USB
By Don Dorward VA3DDN
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What does OTC mean?
OTC is short for “On-The-Go.”
OTC USB cables are made with five pins at the Micro or
Mini end instead of four. The extra pin (#4) is sensed by OTC
capable Android devices to allow them to communicate with
peripheral devices such as USB storage, keyboards, etc.
This pin is marked as “ID” on the breakout boards and is
usually connected directly to ground pin 5. This is easily
verified using the USB cable checker.
■ FIGURE 1.
42 July/August 2018
■ FIGURE 2.