Is it Possible?

Thread Starter

The_Apprentice_

Joined Oct 3, 2019
6
Is it possible to create a design that has the ability to test the pinout of cables?
For example If I have a 20 pin male connector and the other end of the cable was a 20 pin female connector would it be possible to connect both male and female end into a device that could confirm that pin 1 on the male side is connected to pin 1 on the female side and that pin 2 on the male side is connected to pin 2 on the female side and so on.
If this is possible how would this be achieved?

Also getting even more complicated, is it possible to create a device to detect more complicated layouts.. For example if my pin 1 on the male side was going to my pin 7 on the female side.

Any input on how I can achieve this would be greatly appreciated!
I'd quite like to create a test box for my college project.
Thanks in advance
 
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Thread Starter

The_Apprentice_

Joined Oct 3, 2019
6
I was wondering how and if it
It's possible to create a circuit that has the ability to test the pinout of cables?
For example If I have a 20 pin male connector and the other end of the cable was a 20 pin female connector would it be possible to connect both male and female end into a device that could confirm that pin 1 on the male side is connected to pin 1 on the female side and that pin 2 on the male side is connected to pin 2 on the female side and so on.

If this is possible how can this be achieved?

Also getting even more complicated, is it possible to create a device to detect more complicated layouts.. For example if my pin 1 on the male side was going to my pin 7 on the female side.

Any input on how I can achieve this would be greatly appreciated!
I'd quite like to create a test box for my college project.
Thanks in advance
 

eetech00

Joined Jun 8, 2013
1,726
Is it possible to create a design that has the ability to test the pinout of cables?
For example If I have a 20 pin male connector and the other end of the cable was a 20 pin female connector would it be possible to connect both male and female end into a device that could confirm that pin 1 on the male side is connected to pin 1 on the female side and that pin 2 on the male side is connected to pin 2 on the female side and so on.
If this is possible how would this be achieved?

Also getting even more complicated, is it possible to create a device to detect more complicated layouts.. For example if my pin 1 on the male side was going to my pin 7 on the female side.

Any input on how I can achieve this would be greatly appreciated!
I'd quite like to create a test box for my college project.
Thanks in advance
yes...automated cable testers have been around for decades...

eT
 

AnalogKid

Joined Aug 1, 2013
8,157
Cable testers, a pieces of electronic test equipment, have been around for decades. Modern ones don't have to be programmed manually - you connect a "known-good" cable and it learns all possible correct and incorrect connections. When it detects an error, it gives complete details about what is incorrect.

If you want to build one from scratch, a tester for a simple straight-through cable such as you describe can be pretty simple. One approach is to make two mating connectors. One has the pins daisy-chained: 1 is connected to 2, 3 is connected to 4, 5 is connected to 6, etc. The other has pins 1 and 20 brought out with long wires. Pins 2-19 are daisy-chained: 2 is connected to 3, 4 is connected to 5, etc. When everything is connected, a correct cable appears as a straight connection from pin 1 to pin 20, zig-zagging through all 20 wires. This can be indicated with a battery and a beeper or LED. Note that this type of tester indicates a bad cable, but gives no details about the problem. Also, there are some combinations of incorrect connections that appear correct, but those are very rare.

ak
 

AlbertHall

Joined Jun 4, 2014
8,551
For a simple go/no go test you might use something like the below circuit. It connects all the wires in the cable in series but with resistors forming the links. Thus the cable below should read three times the resistor value. Any short circuit or mis-wiring will give a lower reading. It doesn't tell you anything about the fault location or type however.

1573686874024.png
 

dl324

Joined Mar 30, 2015
9,154
Here's one suggestion from Signetics:
1573687789854.png
1573687812961.png

If you don't want to build your own, search the web. I have one that checks RJ-45 (8 wires).

Similar to this:
1573687913410.png

Also getting even more complicated, is it possible to create a device to detect more complicated layouts.. For example if my pin 1 on the male side was going to my pin 7 on the female side.
For this, I'd probably opt for an Arduino based solution. For 40 I/O's, you'd need a Mega.
 

crutschow

Joined Mar 14, 2008
23,542
See this thread.

If you want to test each connection for opens, shorts, or crossed wires, then you could use a multiplexer to sequentially apply a signal to each wire with a LED at the end of each wire to detect the signal.
That also has the advantage of immediately telling you exactly which wires are miswired by watching the light sequence.

You could use two 16-channel CD14067 muxes, or three 8-channel CD4051 muxes.
They can be sequenced using a 555 astable clock driving two CD4162/40163 4-bit counters to generate the sequential mux address signals.
 
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Marley

Joined Apr 4, 2016
294
Of course you could automate the multiplexer with a micro-controller that would scan though all the combinations and give a result on an LCD display. Either "passed" or "short between 1 & 2" (for example).
 
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