Checking CAT6 & Coax Continuity

[TX63CONV]

Maybe continuity is not the right term. I posted here a month ago about running CAT 6 and COAX cable to various rooms in my house and received tons of helpful feedback. The cables are in and I wanted to check to make sure there were not any issues (breaks, grounds, etc) with running the lines.

Is there a way to check the continuity using my multi-meter?

 

[Gary S]

You can do it, but it gets a bit complicated. You short two wires of the Cat 6 together at one end. At the other end, you measure from one of those wires to the other for continuity. You should have continuity with them shorted together, and read an open with the short disconnected. You can do the same with coax. Measure from shield to center on one end. You should read an open circuit indicating that the cable isn't internally shorted. Then short them at the end opposite of the one you are measuring, and you should see a short at your end.
There is a much easier way. I have a cheap tester that I connect the transmitter to one end of the coax or Cat 5/6. Then I connect the receiver to the other end. A series of LEDs on the receive end blink either green or red for each pair of wires to indicate good or bad. The tester cost under $20.

 

[lametec]

Buy an RJ45 tester on ebay or somewhere else. They check for continuity and shorts, and only cost a few bucks.

I have one I bought long time ago from Meritline, and while it's not a high quality tool, it does work.

 

[theoldwizard1]

Is there a way to check the continuity using my multi-meter?

Not really.

You have to send a "signal" down the wire. Simply checking resistance and continuity while a good first step is not enough,

 

[stirling]

The problem with the method of shorting wires and checking continuity with your multi-meter is that it doesn't check with the end on the cable, and that's where the trouble usually is if there is any. The cheap cat testers ($10.00 or less on ebay) will at least let you know that you don't have any miswires and that you have continuity. They aren't much good for commercial use, but should be fine for what you want to do.

 

[Gary S]

The problem with the method of shorting wires and checking continuity with your multi-meter is that it doesn't check with the end on the cable, .

If you short the two conductors together through the connector, it does check the connector.

 

[MrMark]

I would use a nine volt battery on one end and the multimeter on the other for the coax. Connect between center conductor and the grounded shielding.

 

[Socophreak]

Buy an RJ45 tester on ebay or somewhere else. They check for continuity and shorts, and only cost a few bucks.

I have one I bought long time ago from Meritline, and while it's not a high quality tool, it does work.

This. You should be able to find them around at almost any local electronics store.

 

[jon.human]

if you have a dish network rcvr plug it into the input port and at the other end it will read +/- 19 volts

 

[shoturtle]

Have you cut down the ends yet of the coax and the cat6?

 

[ddawg16]

I have a 50 ohm termination that I can put on one end....then on the other end I just measure for the resistance from center conductor to shield.

You can buy an Ethernet continuity tester for about $20. The cheap one I have has a module I can stick on the other end...hit the test button on the main module...go to the other end and make sure the LED's flash in sequence....if so...it's wired right.

 

[gt40mkii]

Here's what I'd do -- nothing.

Install the cable, put connectors on the ends, and then hook up whatever you're going to use it for and see if it works. If it does, great. If it doesn't, then it's time to inspect the cable for anomalies. (You'er not likely to see any any replace the cable any way.)

You're only going to be able to test the most basic things without buying equipment. Sending a signal down the line is going to require more than a multimeter or a basic continuity tester.

The reality is, I've strung miles of cable in IT environments with lots of twists, turns and other abuses and I've yet to see a bad network cable. LOTS of bad connectors, sure, but I don't think I can remember a cable ever being bad after installation. (In the cases where a "cable" was bad, I cut off the connectors and attached new ones, which fixed the problem -- even for commercially-terminated cables.)

 

[Gary S]

This cheap thing actually works. I have one similar to it and have been using it for almost 10 years.
http://www.google.com/products/cata...a=X&ei=MGpiT9epKYOWgweoxKnxAg&ved=0CH4Q8wIwAA

 

[TX63CONV]

Thanks for all the advice. What I was hoping to do was test before drywall goes up. I have a several extra runs to use if one is band and like GT40 said the problem will probably be in the connection.

I might check out the tester if I can find one locally.

Thanks!

 

[Gary S]

If you have a Menards near you, they carry one, but it will cost more than the really cheap ones online.
http://www.google.com/products/cata...a=X&ei=MGpiT9epKYOWgweoxKnxAg&ved=0CH4Q8wIwAA

Office Depot has them too for similar price.
http://www.officedepot.com/a/products/972170/Tripp-Lite-Multi-Functional-Network-Cable/

 

[71flh]

I think before you get to the finish stage, the ends won't be terminated and you'll have nothing to test. As far as CATx, you need to connect the cables to something to check.

When testing, realize that the signal in the wire s is a variable, somewhat high frequency square wave, which in electrical terms begins to act like AC. This is where termination becomes important.