Cat5 Coupler Problems

[jmjudy2 0]

Hi, I've got 5 POE cameras connected to an NVR. I'm using existing Cat5 cables that were installed when our house was built 15 years ago. I terminated the old cables and used a coupler to connect the patch cords to the POE cameras. I got everything working with great help from folks here.

 

However, the cameras stopped working soon as I used cheap couplers. I got some good advice and used a more rugged one, the Neutrik etherCON RJ45 Feed-Through Coupler for Cable Extensions.

 

After several months of use 3 of them have gone out. I had a couple of extra that I had bought and they've stopped working after several weeks.

 

Are there better ones or should I try the punch down boxes that may provide a better connection?

 

Thanks in advance!

[Daryl733 0]

Did you crimp the wire in the correct order ?

http://www.groundcontrol.com/galileo/ch5-ethernet.htm

 

Do note the 4/5 and the 3/6 wire's pairing.

 

One common mistake is to pair 1/2 3/4 5/6 7/8 which goes against the specification.

It works for short distance, but if distance or interference is large, you'll encounter intermittent problem.

That's the problem we always faced when people diy or have their electrician who know nuts about network cabling crimp the cables for them.

 

The pairing pattern is used to reduce interference. If you are interested to read more, google for it.

 

Otherwise, get a network cable tester and test if the crimp is good and there's no break in the cable.

[jmjudy2 0]

Thanks! I'll check this weekend.

 

I really appreciate the help.

[jmjudy2 0]

Looks like my problem might be that my old Cat5 cables are wired with the old T-568A Straight-Through Ethernet standard. My house was wired in 2001 and looks like all my connectors are wired that way.

 

Guess I need to keep that pattern when I connect to the new patch cables?

[Daryl733 0]

Nothing wrong with T-568A. You'll just have to keep it consistent at both end of the cable.

It'll work even if your extension cable is T-568B. Bascially the wiring order is the same, just color coding is different. Both end of the same stretch of cable have to match.

 

You always have to keep to the pattern.

 

There's a reason for it.

If you want to read more, google for it.

 

Basically the no. of twist is different for each of the 4 pairs in order to subject them to different level of interference.

When the signal get interference, it'll affect each pair the same way, resulting in the voltage differences between each pair to remain the same.

That's how the signal is derived. Instead of trying to prevent (shield) the cable from interference, it allows for it to happens and is able to correct from it.

 

However when you wire the wrong pattern, each signal is no longer passed through the same pair, interference will no longer be corrected, leading to unstable network connection.

 

Now, back to your immediate problem.

Couplers are basically female to female joints that allow you to join 2 cables together.

They have no electronic parts in them.

They shouldn't spoil that easily.

Check the surface of the connection. Could be the environment you install them is causing corrosion or something that affect the connectivity. If you see oxidation, take a sandpaper and sand the surface and try again. but it's only a interim solution. You may want to contain the join in a waterproof box.

[jmjudy2 0]

Checked all the wiring with the tester and got them straight now. The recommended couplers and other equipment from the forum are rock solid. Think the cameras should be getting less interference. Did find one camera that had failed and am replacing it.

 

Thanks for all the great and timely advice!