I have a customer whose house is wired with Cat 5. They get 2 dialtones from their digital cable company, and each jack is a homerun. The problem is, you can hear the DTMF tones of someone on line 2, when you're talking on line 1. The customer claims you can hear conversations also. When you unplug from the Cat5, and listen with a butt-set, the dialtone is clear. Any ideas
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Cross talk on Cat 5 wiring
- Thread starter fsoz
- Start date
Dear Fsoz,
May be crosstalk issue.
1. Check each jack termination and make sure no cable stubs exist(cut side of termination) causing mini-antenna reception/transmittal. Reterminate (low setting) cable to jack.
2. If you have a CAT5 tester (Attenuation and NEXT), test line 1 and line 2 at each jack location to make sure they meet standards. I realize the phones don't use megabit speeds but it may show a termination problem or cable insulation jacket pulled back too far(1/2"max).
3. Possible staple nick in cable.If you don't have a CAT5 tester use contuity tester to see if short may be acting as antenna.
Regards,
Peter
May be crosstalk issue.
1. Check each jack termination and make sure no cable stubs exist(cut side of termination) causing mini-antenna reception/transmittal. Reterminate (low setting) cable to jack.
2. If you have a CAT5 tester (Attenuation and NEXT), test line 1 and line 2 at each jack location to make sure they meet standards. I realize the phones don't use megabit speeds but it may show a termination problem or cable insulation jacket pulled back too far(1/2"max).
3. Possible staple nick in cable.If you don't have a CAT5 tester use contuity tester to see if short may be acting as antenna.
Regards,
Peter
AvayaNovice
Vendor
I'd say crosstalk is a good possibility...
FSOZ, when you're listening with your buttset, where were you at? The MPOE from the cable company? How are these wires terminated? Is there some sort of a block? What kind of jacks? I'd guess that it's the termination. Considering the twistes pair nature of Cat-5, cross talk in the actual cable is very unlikely unless like buitenhek said -- a staple got in there.
I'd re-terminate and insure that that everything is clean. Are you ONLY hearing DTMF? Where are you located? If you know testing numbers for your CO in your area, try using a test tone to see if you can hear it bleeding into the other line. Also... if they're all homeruns, you might want to try just connecting one of the jacks and see if you get the same problem on each one individually. Like BobG1 said, it's also a possibility of the telephone itself (if it is a multiline set).
Nick
FSOZ, when you're listening with your buttset, where were you at? The MPOE from the cable company? How are these wires terminated? Is there some sort of a block? What kind of jacks? I'd guess that it's the termination. Considering the twistes pair nature of Cat-5, cross talk in the actual cable is very unlikely unless like buitenhek said -- a staple got in there.
I'd re-terminate and insure that that everything is clean. Are you ONLY hearing DTMF? Where are you located? If you know testing numbers for your CO in your area, try using a test tone to see if you can hear it bleeding into the other line. Also... if they're all homeruns, you might want to try just connecting one of the jacks and see if you get the same problem on each one individually. Like BobG1 said, it's also a possibility of the telephone itself (if it is a multiline set).
Nick
daronwilson
Vendor
Good advice. This is typical crosstalk and can be most anywhere. If it were me, I'd disconnect the house wiring and check it out right where you get the two dial tones from the cable company and make sure they are clean there. One way is to use two buttsets and call a recording on one line, set that one down, then listen on the other after dialing a digit and see if you hear the recording. Might as well know you have two clean lines before you tear the house wiring apart.
If they are clean there, take the customer's phone and plug it in there and test again. Cheap phones do this quite often.
It's some basic troubleshooting, add one wire/jack into the clean system at a time, and then test.
Good Luck!
It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com
If they are clean there, take the customer's phone and plug it in there and test again. Cheap phones do this quite often.
It's some basic troubleshooting, add one wire/jack into the clean system at a time, and then test.
Good Luck!
It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com
TouchToneTommy
Vendor
Just because it is wired with cat 5, doesn't mean that you are using pairs of wires for each line. I seen it often enough that someone uses two tips for one line and two rings for the other, or uses Green/White because it's the closest to Green, and Orange/White because it's the closest to Red, and then who knows what for the 2nd pair.
Check the color codes, disconnect at the MPOE, reconnect one cat 5 at a time and see if you can isolate it to one particular run.
Check the color codes, disconnect at the MPOE, reconnect one cat 5 at a time and see if you can isolate it to one particular run.
AvayaNovice
Vendor
Good point. Not everyone who does the wiring does it correctly, pair for pair (although in the case of Cat-5, I would think they would considering its twisted pair nature -- but still).
- Thread starter
- #8
It's already been Cat 5 tested, each homerun. There are no split pairs. There is 1 CAT5 cable running from the outside box, up to the attic through a pvc conduit. In the attic all the homeruns are punched down on 66 blocks, and the two dialtones are terminated on RJ-11's. From the RJ-11's, the first dialtone is looped to each blue pair on the 66 block, and the 2nd dialtone is looped and punched on all of the green pairs. All of the homeruns are terminated with CAT5 jacks, and the phones are 2 line portables, using 2 pair cables. We never heard any actual crosstalk conversations, but with our butt sets, we could hear DTMF inside the house, but not outside, when the cables were disconnected
AvayaNovice
Vendor
How'd that even happen? Just randomly? If you only hear it with your buttsets, and only inside... is there a chance that you had a loose connection with your buttset, or that your buttset was picking up the DTMF because they're a little bit stronger? For instance... if you place the ABN clips from your buttset CLOSE to a 66 block that has tone coming through on a pair, it will pick up the tone. DTMF is a little stronger than someone just talking, it could easily pick that up...
If you had tested the cables with a butt set, the cables shouldn't have anything to do with it. It is deffinately the phones. I own a company called Capitol Communications in New Jersey and 5 out of 10 installations I replace cheap 2 or 4 line business sets that were bought at either Staples or Office Max. Every customer that had those phones had the same Cross- Talk problem.
AvayaNovice
Vendor
mattgray is definetely right on that one. Multiline sets that aren't of very good quality have crosstalk problems frequently. Although I've heard from a certain someone, that if you use a twisted pair patch cord from jack to telephone, sometimes it alleviates the problem... but that's unrealistic for a standard telephone.
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