Can't connect to or find Dahua cams

samplenhold said:
Sorry to say this, but it looks like you will have to pull the cam and use a short line to directly connect it to the POE switch. You have tried each POE port, right?
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Yea looks like it. I haven't tried every PoE switch but the one I'm trying is the one I had the previously setup cam connected to so I highly doubt there is an issue with the port. I'll try nonetheless.

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If you have a cable tester, a cheap pair tester, have a look at those cables just to be sure. The same error being repeated is not an unheard of phenomenon.
 
my money's on poor wiring. i'm guessing it's new and somebody didn't crimp the ends properly... of course, you'll need to access the cam locations to confirm/correct,
 
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sebastiantombs said:
If you have a cable tester, a cheap pair tester, have a look at those cables just to be sure. The same error being repeated is not an unheard of phenomenon.
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Yes definitely I have a tester so will check the cables when I remove the cameras.
samplenhold said:
Not other switches, but the other POE ports on that switch. There are 4 POE ports.
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Sorry I did mean other PoE ports...
 
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A cable can pass a continuity check with a cheap tester an still not wok. The cheap tester does not test data rates or standards. What standard are you using for the cable wiring. The cable must have the correct color going to the correct pins, and with the correct twists.
 
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SouthernYankee said:
A cable can pass a continuity check with a cheap tester an still not wok. The cheap tester does not test data rates or standards. What standard are you using for the cable wiring. The cable must have the correct color going to the correct pins, and with the correct twists.
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I'm using T-568B. The camera cable at the switch end is wired to this standard. When I take the cameras off I'll check the wiring on that end is also to this standard.

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OK so I only had time today to take one of the cameras down but when I did, I found the problem instantly. The wiring at the camera end was back to front, i.e. he had attempted to follow T-568B but had wired it in reverse order!! What an absolute tool! To make matters worse, despite my repeated reminders he had left very little cable in the wall mount so I didn't have much to work with. And to add the cherry on top, even after I managed to crimp another connector on correctly, I couldn't connect to the camera. After much checking I took the camera off again to find that somehow, one of the brass piercings on the connector was missing - it must have got damaged and broken during crimping or testing. That meant a second new connector and even less cable to work with but I managed it and the good news is the perseverance paid off and I finally have the camera up and running.

I'm expecting back to front wiring at the other camera too but will check tomorrow hopefully and report back.

I will make sure I never use that electrician again...
 
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freddyq said:
OK so I only had time today to take one of the cameras down but when I did, I found the problem instantly. The wiring at the camera end was back to front, i.e. he had attempted to follow T-568B but had wired it in reverse order!! What an absolute tool! To make matters worse, despite my repeated reminders he had left very little cable in the wall mount so I didn't have much to work with. And to add the cherry on top, even after I managed to crimp another connector on correctly, I couldn't connect to the camera. After much checking I took the camera off again to find that somehow, one of the brass piercings on the connector was missing - it must have got damaged and broken during crimping or testing. That meant a second new connector and even less cable to work with but I managed it and the good news is the perseverance paid off and I finally have the camera up and running.

I'm expecting back to front wiring at the other camera too but will check tomorrow hopefully and report back.

I will make sure I never use that electrician again...
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A lot of electricians don't have a clue about proper ethernet wiring. You need to use someone that is certified for low voltage work.
 
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a bit of a hack, but if you don't want to dismount the other cam, just re-do the NVR end the same backwards way. while not 'to standard', it will work 100%.
then LABEL that wire, if you like, but it really doesn't matter, as long as the pairs are preserved (which a straight inversion does)

IE, as long as both ends are the same, and you have a pair in the middle, a pair straddling that middle pair, and pair on either side, it's 100% functional.
 
pozzello said:
a bit of a hack, but if you don't want to dismount the other cam, just re-do the NVR end the same backwards way. while not 'to standard', it will work 100%.
then LABEL that wire, if you like, but it really doesn't matter, as long as the pairs are preserved (which a straight inversion does)

IE, as long as both ends are the same, and you have a pair in the middle, a pair straddling that middle pair, and pair on either side, it's 100% functional.
Click to expand...
Interesting, I didn't think of that! The other cam is more accessible than the one I took down today so I might still remove it but if it is indeed wired in reverse and again cable is limited, I might go with your suggestion!

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568b2.jpg
 
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