Developing a simple twisted pair cable tester
At the moment I am an applicant, as well as people born in 94 there was little in Ukraine; many departments of higher educational institutions did little “scientific” work with students in grades 10–11. Participant of such work was lucky to become me. I got on fak. TCET KNURE, namely to the senior teacher Malinin A.P.
I was asked to create a simple cable tester, the creation of which I will try to describe in this article.
My task was to create a simple device that allows testing the UTP cable of category 5 (can be implemented for any cable on a twisted pair) which is able to diagnose these types of errors:
- cliffs;
- short circuit;
- coup coup;
- intersections of pairs;
I left the diagnosis of pair splitting for senior students, as with such an error the physical connection remains, and the resistance to interference changes (a tone generator seems to be needed, but I didn’t really go into it - it’s too difficult for me).
')
The device itself consists of 2 parts (let's call them passive and active).
The logical diagram of the device:
So the task of the active part of the tester is the distribution of pulses physically and in time.
Tobish at the counter outputs (A1, A1, A3, A4) should be like this:
A1 1 0 0 0
A1 0 1 0 0
A3 0 0 1 0
A4 0 0 0 1
Each pulse will “run” along its own pair, and if there are no cliffs and the cable is crimped correctly, the green LEDs will light up in turn on the “passive” part.
What happens when errors in crimping or cable breaks?
Breaks, short circuits : all or several LEDs do not light up, since the circuit is not closed and the current just does not flow.
Coupling of the pair : the red diode will light up (the color naturally does not matter, but I did not invent a bicycle), since the current will flow in another direction (not x1> x2, a x2> x1), which will cause a non-green diode to catch fire.
Intersection of pairs : LEDs on the "passive" part will light up in turns.
Of course, this device is far from perfect, but still better than a simple “dial”. Unfortunately, I don’t have any photos to post, I can only say that at a price the tester turned out to be 2 times cheaper than the cheapest Chinese counterparts, although not very decent people trade on the Kharkov radio market = (
The tester itself was implemented on a montage, 3 microchips (inverter, counter, decoder), 8 LEDs, 2 sockets and all other trifles (resistor and capacitor).
I was asked to create a simple cable tester, the creation of which I will try to describe in this article.
My task was to create a simple device that allows testing the UTP cable of category 5 (can be implemented for any cable on a twisted pair) which is able to diagnose these types of errors:
- cliffs;
- short circuit;
- coup coup;
- intersections of pairs;
I left the diagnosis of pair splitting for senior students, as with such an error the physical connection remains, and the resistance to interference changes (a tone generator seems to be needed, but I didn’t really go into it - it’s too difficult for me).
')
The device itself consists of 2 parts (let's call them passive and active).
The logical diagram of the device:
So the task of the active part of the tester is the distribution of pulses physically and in time.
Tobish at the counter outputs (A1, A1, A3, A4) should be like this:
A1 1 0 0 0
A1 0 1 0 0
A3 0 0 1 0
A4 0 0 0 1
Each pulse will “run” along its own pair, and if there are no cliffs and the cable is crimped correctly, the green LEDs will light up in turn on the “passive” part.
What happens when errors in crimping or cable breaks?
Breaks, short circuits : all or several LEDs do not light up, since the circuit is not closed and the current just does not flow.
Coupling of the pair : the red diode will light up (the color naturally does not matter, but I did not invent a bicycle), since the current will flow in another direction (not x1> x2, a x2> x1), which will cause a non-green diode to catch fire.
Intersection of pairs : LEDs on the "passive" part will light up in turns.
Of course, this device is far from perfect, but still better than a simple “dial”. Unfortunately, I don’t have any photos to post, I can only say that at a price the tester turned out to be 2 times cheaper than the cheapest Chinese counterparts, although not very decent people trade on the Kharkov radio market = (
The tester itself was implemented on a montage, 3 microchips (inverter, counter, decoder), 8 LEDs, 2 sockets and all other trifles (resistor and capacitor).
Source: https://habr.com/ru/post/125069/
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